[llvm] [AArch64] Drop flags from BSP pseudos (PR #151856)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-ubuntu` running on `linaro-lldb-aarch64-ubuntu` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/22297

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: lang/c/global_variables/TestGlobalVariables.py (754 of 2304)
PASS: lldb-api :: lang/c/local_variables/TestLocalVariables.py (755 of 2304)
PASS: lldb-api :: lang/c/offsetof/TestOffsetof.py (756 of 2304)
XFAIL: lldb-api :: lang/c/modules/TestCModules.py (757 of 2304)
PASS: lldb-api :: lang/c/non-mangled/TestCNonMangled.py (758 of 2304)
PASS: lldb-api :: lang/c/record_decl_in_expr/TestRecordDeclInExpr.py (759 of 2304)
PASS: lldb-api :: lang/c/parray_vrs_char_array/TestParrayVrsCharArrayChild.py (760 of 2304)
PASS: lldb-api :: lang/c/sizeof/TestCSizeof.py (761 of 2304)
PASS: lldb-api :: lang/c/register_variables/TestRegisterVariables.py (762 of 2304)
UNRESOLVED: lldb-api :: functionalities/statusline/TestStatusline.py (763 of 2304)
******************** TEST 'lldb-api :: functionalities/statusline/TestStatusline.py' FAILED ********************
Script:
--
/usr/bin/python3.10 /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./lib --env LLVM_INCLUDE_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/include --env LLVM_TOOLS_DIR=/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin --arch aarch64 --build-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex --lldb-module-cache-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/lldb --compiler /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/clang --dsymutil /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin/dsymutil --make /usr/bin/gmake --llvm-tools-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./bin --lldb-obj-root /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/tools/lldb --lldb-libs-dir /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/./lib --cmake-build-type Release /home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/functionalities/statusline -p TestStatusline.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 22.0.0git (https://github.com/llvm/llvm-project.git revision 229ab5aa2b11bb8738db2810677abfc89050ad80)
  clang revision 229ab5aa2b11bb8738db2810677abfc89050ad80
  llvm revision 229ab5aa2b11bb8738db2810677abfc89050ad80
Skipping the following test categories: ['libc++', 'msvcstl', 'dsym', 'gmodules', 'debugserver', 'objc']

--
Command Output (stderr):
--
PASS: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test (TestStatusline.TestStatusline)
PASS: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test_deadlock (TestStatusline.TestStatusline)
lldb-server exiting...
FAIL: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test_modulelist_deadlock (TestStatusline.TestStatusline)
PASS: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test_no_color (TestStatusline.TestStatusline)
PASS: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test_no_target (TestStatusline.TestStatusline)
PASS: LLDB (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/bin/clang-aarch64) :: test_resize (TestStatusline.TestStatusline)
======================================================================
ERROR: test_modulelist_deadlock (TestStatusline.TestStatusline)
   Regression test for a deadlock that occurs when the status line is enabled before connecting
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/functionalities/statusline/TestStatusline.py", line 199, in test_modulelist_deadlock
    self.expect(
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbpexpect.py", line 94, in expect
    self.child.expect_exact(s)
  File "/usr/local/lib/python3.10/dist-packages/pexpect/spawnbase.py", line 432, in expect_exact
    return exp.expect_loop(timeout)
  File "/usr/local/lib/python3.10/dist-packages/pexpect/expect.py", line 179, in expect_loop
    return self.eof(e)
  File "/usr/local/lib/python3.10/dist-packages/pexpect/expect.py", line 122, in eof
    raise exc

```

</details>

https://github.com/llvm/llvm-project/pull/151856