[llvm] [X86] Fix Sandy Bridge's WriteLDMXCSR (PR #203585)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `llvm` at step 6 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/47480

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

```
Step 6 (test-build-unified-tree-check-flang) failure: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
...
PASS: Flang :: Lower/zero_init_default_init.f90 (2737 of 4580)
PASS: Flang :: Driver/fdebug-info-for-profiling.f90 (2738 of 4580)
PASS: Flang :: Lower/math-lowering/exp.f90 (2739 of 4580)
PASS: Flang :: Lower/power-operator.f90 (2740 of 4580)
PASS: Flang :: Profile/gcc-flag-compatibility.f90 (2741 of 4580)
PASS: Flang :: Semantics/OpenACC/acc-default-none-scalars-strict.f90 (2742 of 4580)
PASS: Flang :: Driver/integer-overflow.f90 (2743 of 4580)
PASS: Flang :: Semantics/OpenMP/implicit_linear_symbols.f90 (2744 of 4580)
PASS: Flang :: Lower/OpenMP/rtl-flags.f90 (2745 of 4580)
PASS: Flang :: Driver/fopenmp-simd.f90 (2746 of 4580)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=3243.056496
Step 7 (test-build-unified-tree-check-flang-rt) failure: 1200 seconds without output running [b'ninja', b'check-flang-rt'], attempting to kill
...
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/39/309 (293 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/42/309 (294 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/38/309 (295 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/34/309 (296 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/145/309 (297 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/148/309 (298 of 318)
PASS: flang-rt :: Driver/compare_iso_fortran_env_symbols.f90 (299 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/151/309 (300 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/152/309 (301 of 318)
PASS: flang-rt-Unit :: Runtime/./RuntimeTests/147/309 (302 of 318)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang-rt'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1456.116476

```

</details>

https://github.com/llvm/llvm-project/pull/203585