[llvm] [lit] Implement builtin umask (PR #94621)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/1324

Here is the relevant piece of the build log for the reference:
```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
...
PASS: AddressSanitizer-x86_64-linux :: TestCases/leaks.cpp (863 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_rev-bfloat.c (864 of 84300)
PASS: cfi-devirt-lld-x86_64 :: base-derived-destructor.cpp (865 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_trn2-bfloat.c (866 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_pfirst.c (867 of 84300)
PASS: Clang :: CodeGen/aarch64-sme2-intrinsics/acle_sme2_cvtn.c (868 of 84300)
PASS: MemorySanitizer-X86_64 :: readdir64.cpp (869 of 84300)
PASS: Clang :: OpenMP/declare_variant_device_kind_codegen.cpp (870 of 84300)
PASS: UBSan-ThreadSanitizer-x86_64 :: TestCases/Pointer/align-assume-attribute-align_value-on-paramvar.cpp (871 of 84300)
UNRESOLVED: Clang :: utils/update_cc_test_checks/generated-funcs.test (872 of 84300)
******************** TEST 'Clang :: utils/update_cc_test_checks/generated-funcs.test' FAILED ********************
Exception during script execution:
Traceback (most recent call last):
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/worker.py", line 76, in _execute_test_handle_errors
    result = test.config.test_format.execute(test, lit_config)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/formats/shtest.py", line 29, in execute
    return lit.TestRunner.executeShTest(
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 2295, in executeShTest
    return _runShTest(test, litConfig, useExternalSh, script, tmpBase)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 2239, in _runShTest
    res = runOnce(execdir)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 2215, in runOnce
    res = executeScriptInternal(
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 1091, in executeScriptInternal
    exitCode, timeoutInfo = executeShCmd(
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 205, in executeShCmd
    finalExitCode = _executeShCmd(cmd, shenv, results, timeoutHelper)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 707, in _executeShCmd
    res = _executeShCmd(cmd.lhs, shenv, results, timeoutHelper)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 707, in _executeShCmd
    res = _executeShCmd(cmd.lhs, shenv, results, timeoutHelper)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 707, in _executeShCmd
    res = _executeShCmd(cmd.lhs, shenv, results, timeoutHelper)
  [Previous line repeated 13 more times]
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 712, in _executeShCmd
    res = _executeShCmd(cmd.rhs, shenv, results, timeoutHelper)
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/TestRunner.py", line 892, in _executeShCmd
    subprocess.Popen(
TypeError: __init__() got an unexpected keyword argument 'umask'


********************
PASS: Clang :: Driver/clang-translation.c (873 of 84300)
PASS: Clang :: CodeGen/aarch64-sme2-intrinsics/acle_sme2_vdot.c (874 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_ldff1ub.c (875 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_ld4-bfloat.c (876 of 84300)
PASS: Clang :: CodeGen/aarch64-sve-intrinsics/acle_sve_uzp2.c (877 of 84300)
PASS: UBSan-AddressSanitizer-lld-x86_64 :: TestCases/Pointer/nullptr-and-nonzero-offset-variable.cpp (878 of 84300)
PASS: LLVM :: tools/llvm-readobj/ELF/file-header-machine-types.test (879 of 84300)

```

https://github.com/llvm/llvm-project/pull/94621