[compiler-rt] [libfuzzer] use timer_create() instead of setitimer() for linux (PR #110274)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-windows` running on `sanitizer-windows` while building `compiler-rt` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/107/builds/4881

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

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/sanitizer-windows.py ...' (failure)
...
Total Discovered Tests: 680
  Unsupported      : 237 (34.85%)
  Passed           : 430 (63.24%)
  Expectedly Failed:  13 (1.91%)

1 warning(s) in tests
[124/127] Running the AddressSanitizer tests with dynamic runtime
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\llvm\utils\lit\lit\llvm\config.py:57: note: using lit tools: C:\gnuwin32\bin
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\lit.common.cfg.py:60: warning: Path reported by clang does not exist: "C:\b\slave\sanitizer-windows\build\stage1\lib\clang\20\lib\x86_64-pc-windows-msvc". This path was found by running ['C:/b/slave/sanitizer-windows/build/stage1/./bin/clang.exe', '--target=x86_64-pc-windows-msvc', '-print-runtime-dir'].
-- Testing: 540 tests, 16 workers --
command timed out: 1200 seconds without output running ['python', '../llvm-zorg/zorg/buildbot/builders/annotated/sanitizer-windows.py', '--jobs=16'], attempting to kill
program finished with exit code 1
elapsedTime=2067.439000
Testing:  0.. 10.. 20.. 30.. 40..
Step 8 (stage 1 check) failure: stage 1 check (failure)
...

Testing Time: 22.23s

Total Discovered Tests: 827
  Unsupported: 478 (57.80%)
  Passed     : 349 (42.20%)

2 warning(s) in tests
[117/127] Generating Fuzzer-x86_64-Test.exe
   Creating library C:\b\slave\sanitizer-windows\build\stage1\projects\compiler-rt\lib\fuzzer\tests\.\Fuzzer-x86_64-Test.lib and object C:\b\slave\sanitizer-windows\build\stage1\projects\compiler-rt\lib\fuzzer\tests\.\Fuzzer-x86_64-Test.exp

[121/127] Generating X86_64WindowsDynamicConfig/Asan-x86_64-calls-Dynamic-Test.exe
[122/127] Running libFuzzer tests
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\llvm\utils\lit\lit\llvm\config.py:57: note: using lit tools: C:\gnuwin32\bin
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\lit.common.cfg.py:60: warning: Path reported by clang does not exist: "C:\b\slave\sanitizer-windows\build\stage1\lib\clang\20\lib\x86_64-pc-windows-msvc". This path was found by running ['C:/b/slave/sanitizer-windows/build/stage1/./bin/clang.exe', '--target=x86_64-pc-windows-msvc', '-print-runtime-dir'].
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\fuzzer\lit.cfg.py:34: note: lsan feature unavailable
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\fuzzer\lit.cfg.py:43: note: msan feature unavailable
-- Testing: 176 tests, 16 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 

Testing Time: 453.72s

Total Discovered Tests: 196
  Unsupported:  48 (24.49%)
  Passed     : 148 (75.51%)

1 warning(s) in tests
[123/127] Running the AddressSanitizer tests
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\llvm\utils\lit\lit\llvm\config.py:57: note: using lit tools: C:\gnuwin32\bin
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\lit.common.cfg.py:60: warning: Path reported by clang does not exist: "C:\b\slave\sanitizer-windows\build\stage1\lib\clang\20\lib\x86_64-pc-windows-msvc". This path was found by running ['C:/b/slave/sanitizer-windows/build/stage1/./bin/clang.exe', '--target=x86_64-pc-windows-msvc', '-print-runtime-dir'].
-- Testing: 572 tests, 16 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..

Testing Time: 96.44s

Total Discovered Tests: 680
  Unsupported      : 237 (34.85%)
  Passed           : 430 (63.24%)
  Expectedly Failed:  13 (1.91%)

1 warning(s) in tests
[124/127] Running the AddressSanitizer tests with dynamic runtime
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\llvm\utils\lit\lit\llvm\config.py:57: note: using lit tools: C:\gnuwin32\bin
llvm-lit.py: C:\b\slave\sanitizer-windows\llvm-project\compiler-rt\test\lit.common.cfg.py:60: warning: Path reported by clang does not exist: "C:\b\slave\sanitizer-windows\build\stage1\lib\clang\20\lib\x86_64-pc-windows-msvc". This path was found by running ['C:/b/slave/sanitizer-windows/build/stage1/./bin/clang.exe', '--target=x86_64-pc-windows-msvc', '-print-runtime-dir'].
-- Testing: 540 tests, 16 workers --

command timed out: 1200 seconds without output running ['python', '../llvm-zorg/zorg/buildbot/builders/annotated/sanitizer-windows.py', '--jobs=16'], attempting to kill
program finished with exit code 1
elapsedTime=2067.439000
Testing:  0.. 10.. 20.. 30.. 40..

```

</details>

https://github.com/llvm/llvm-project/pull/110274