[clang] [CIR] Introduce fenv attribute for strict fp handling (PR #211144)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

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

Full details are available at: https://lab.llvm.org/buildbot/#/builders/95/builds/21805

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

```
Step 6 (test-build-unified-tree-check-all) failure: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
...
PASS: SanitizerCommon-lsan-powerpc64le-Linux :: sanitizer_coverage_allowlist_ignorelist.cpp (113671 of 113681)
PASS: LLVM :: CodeGen/ARM/build-attributes.ll (113672 of 113681)
PASS: Clang :: Driver/x86-target-features.c (113673 of 113681)
PASS: LLVM :: Bitcode/invalid.test (113674 of 113681)
PASS: Clang :: Preprocessor/aarch64-target-features.c (113675 of 113681)
PASS: LLVM :: tools/llvm-objdump/ELF/AMDGPU/subtarget.ll (113676 of 113681)
PASS: Clang :: Driver/amdgpu-macros.cl (113677 of 113681)
PASS: LLVM :: Transforms/LoopUnroll/branch-weights-freq/unroll-complete.ll (113678 of 113681)
PASS: Clang :: Driver/linux-ld.c (113679 of 113681)
PASS: Clang :: Driver/cl-options.c (113680 of 113681)
command timed out: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=21087.500786

```

</details>

https://github.com/llvm/llvm-project/pull/211144