[clang] [compiler-rt] [compiler-rt] Realtime Sanitizer: Introduce Realtime Sanitizer (RTSan) backend (PR #92460)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `premerge-monolithic-linux` running on `premerge-linux-1` while building `compiler-rt` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/2414

Here is the relevant piece of the build log for the reference:
```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
...
0.089 [4/4/23] Building CXX object compiler-rt/lib/memprof/CMakeFiles/RTMemprof_dynamic_version_script_dummy.x86_64.dir/dummy.cpp.o
0.091 [3/4/24] Building CXX object compiler-rt/lib/asan/CMakeFiles/RTAsan_dynamic_version_script_dummy.x86_64.dir/dummy.cpp.o
0.095 [2/4/25] Building CXX object compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic_version_script_dummy.x86_64.dir/dummy.cpp.o
0.114 [0/5/26] Linking CXX shared library /build/buildbot/premerge-monolithic-linux/build/lib/clang/19/lib/x86_64-unknown-linux-gnu/libclang_rt.ubsan_standalone.so
0.140 [0/4/27] Linking CXX shared library /build/buildbot/premerge-monolithic-linux/build/lib/clang/19/lib/x86_64-unknown-linux-gnu/libclang_rt.memprof.so
0.141 [0/3/28] Linking CXX shared library /build/buildbot/premerge-monolithic-linux/build/lib/clang/19/lib/x86_64-unknown-linux-gnu/libclang_rt.hwasan_aliases.so
0.143 [0/2/29] Linking CXX shared library /build/buildbot/premerge-monolithic-linux/build/lib/clang/19/lib/x86_64-unknown-linux-gnu/libclang_rt.hwasan.so
0.149 [0/1/30] Linking CXX shared library /build/buildbot/premerge-monolithic-linux/build/lib/clang/19/lib/x86_64-unknown-linux-gnu/libclang_rt.asan.so
24.463 [3/1/1371] cd /build/buildbot/premerge-monolithic-linux/build/runtimes/runtimes-bins && /etc/cmake/bin/cmake --build /build/buildbot/premerge-monolithic-linux/build/runtimes/runtimes-bins/ --target runtimes-test-depends --config Release
ninja: error: 'compiler-rt/lib/rtsan/tests/llvm_gtest', needed by 'compiler-rt/lib/rtsan/tests/RtsanNoInstTestObjects.rtsan_preinit.cpp.x86_64.o', missing and no known rule to make it
FAILED: runtimes/CMakeFiles/runtimes-test-depends /build/buildbot/premerge-monolithic-linux/build/runtimes/CMakeFiles/runtimes-test-depends 
cd /build/buildbot/premerge-monolithic-linux/build/runtimes/runtimes-bins && /etc/cmake/bin/cmake --build /build/buildbot/premerge-monolithic-linux/build/runtimes/runtimes-bins/ --target runtimes-test-depends --config Release
ninja: build stopped: subcommand failed.

```

https://github.com/llvm/llvm-project/pull/92460