[clang] [clang][bytecode] Fix non-initializing `__builtin_shufflevector` (PR #180691)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-aarch64-linux` running on `sanitizer-buildbot8` while building `clang` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/51/builds/31706

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure) (timed out)
...
[201/206] Generating MSAN_INST_GTEST.gtest-all.cc.aarch64.o
[202/206] Generating MSAN_INST_TEST_OBJECTS.msan_test.cpp.aarch64.o
[203/206] Generating Msan-aarch64-Test
[204/206] Generating MSAN_INST_TEST_OBJECTS.msan_test.cpp.aarch64-with-call.o
[205/206] Generating Msan-aarch64-with-call-Test
[205/206] Running compiler_rt regression tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/discovery.py:273: warning: input '/home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/test/interception/Unit' contained no tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/discovery.py:273: warning: input '/home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/Unit' contained no tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 6349 tests, 72 workers --
command timed out: 1200 seconds without output running [b'python', b'../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1611.217973
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
Step 9 (test compiler-rt symbolizer) failure: test compiler-rt symbolizer (failure)
...
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/type_traits.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/typeindex.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/typeinfo.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/unordered_map.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/unordered_set.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/utility.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/valarray.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/variant.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/vector.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std/version.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cassert.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cctype.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cerrno.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cfenv.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cfloat.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cinttypes.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/climits.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/clocale.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cmath.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/csetjmp.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/csignal.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstdarg.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstddef.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstdint.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstdio.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstdlib.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cstring.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/ctime.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cuchar.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cwchar.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat/cwctype.inc
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.cppm
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/share/libc++/v1/std.compat.cppm
-- Installing: /home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/lib/tsan/libcxx_tsan_aarch64/lib/libc++.modules.json
[201/206] Generating MSAN_INST_GTEST.gtest-all.cc.aarch64.o
[202/206] Generating MSAN_INST_TEST_OBJECTS.msan_test.cpp.aarch64.o
[203/206] Generating Msan-aarch64-Test
[204/206] Generating MSAN_INST_TEST_OBJECTS.msan_test.cpp.aarch64-with-call.o
[205/206] Generating Msan-aarch64-with-call-Test
[205/206] Running compiler_rt regression tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/discovery.py:273: warning: input '/home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/test/interception/Unit' contained no tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/discovery.py:273: warning: input '/home/b/sanitizer-aarch64-linux/build/build_default/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/Unit' contained no tests
llvm-lit: /home/b/sanitizer-aarch64-linux/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 6349 tests, 72 workers --

command timed out: 1200 seconds without output running [b'python', b'../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1611.217973
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..

```

</details>

https://github.com/llvm/llvm-project/pull/180691