[llvm] [Transforms/Utils][NFC] Replace SmallPtrSet with vector (PR #186664)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-offload-amdgpu-runtime-2` running on `rocm-worker-hw-02` while building `llvm` at step 10 "Add check check-libc-amdgcn-amd-amdhsa".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/10/builds/24600

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

```
Step 10 (Add check check-libc-amdgcn-amd-amdhsa) failure: test (failure)
...
[ RUN      ] LlvmLibcFMinimumMagNumTest.InfArg
[       OK ] LlvmLibcFMinimumMagNumTest.InfArg (3 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.NegInfArg
[       OK ] LlvmLibcFMinimumMagNumTest.NegInfArg (3 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.BothZero
[       OK ] LlvmLibcFMinimumMagNumTest.BothZero (3 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.Range
[       OK ] LlvmLibcFMinimumMagNumTest.Range (10 ms)
Ran 5 tests.  PASS: 5  FAIL: 0
[2570/3360] Running hermetic test libc.test.src.math.smoke.fmull_test.__hermetic__
FAILED: libc/test/src/math/smoke/libc.test.src.math.smoke.fmull_test.__hermetic__.__cmd__ /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/runtimes/runtimes-amdgcn-amd-amdhsa-bins/libc/test/src/math/smoke/libc.test.src.math.smoke.fmull_test.__hermetic__.__cmd__ 
cd /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/runtimes/runtimes-amdgcn-amd-amdhsa-bins/libc/test/src/math/smoke && /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/bin/llvm-gpu-loader /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/runtimes/runtimes-amdgcn-amd-amdhsa-bins/libc/test/src/math/smoke/libc.test.src.math.smoke.fmull_test.__hermetic__.__build__
[==========] Running 4 tests from 1 test suite.
[ RUN      ] LlvmLibcMulTest.SpecialNumbers
[       OK ] LlvmLibcMulTest.SpecialNumbers (25 us)
[ RUN      ] LlvmLibcMulTest.InvalidOperations
[       OK ] LlvmLibcMulTest.InvalidOperations (6 us)
[ RUN      ] LlvmLibcMulTest.RangeErrors
[       OK ] LlvmLibcMulTest.RangeErrors (7 us)
[ RUN      ] LlvmLibcMulTest.InexactResults
[       OK ] LlvmLibcMulTest.InexactResults (1 us)
Ran 4 tests.  PASS: 4  FAIL: 0
[2571/3360] Running hermetic test libc.test.src.math.smoke.fminimum_mag_numl_test.__hermetic__
[==========] Running 5 tests from 1 test suite.
[ RUN      ] LlvmLibcFMinimumMagNumTest.NaN
[       OK ] LlvmLibcFMinimumMagNumTest.NaN (14 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.InfArg
[       OK ] LlvmLibcFMinimumMagNumTest.InfArg (6 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.NegInfArg
[       OK ] LlvmLibcFMinimumMagNumTest.NegInfArg (4 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.BothZero
[       OK ] LlvmLibcFMinimumMagNumTest.BothZero (4 us)
[ RUN      ] LlvmLibcFMinimumMagNumTest.Range
[       OK ] LlvmLibcFMinimumMagNumTest.Range (11 ms)
Ran 5 tests.  PASS: 5  FAIL: 0
[2572/3360] Running hermetic test libc.test.src.stdbit.stdc_trailing_ones_ull_test.__hermetic__
[==========] Running 2 tests from 1 test suite.
[ RUN      ] LlvmLibcStdcTrailingOnesUllTest.ALL
[       OK ] LlvmLibcStdcTrailingOnesUllTest.ALL (2 us)
[ RUN      ] LlvmLibcStdcTrailingOnesUllTest.ZeroHot
[       OK ] LlvmLibcStdcTrailingOnesUllTest.ZeroHot (3 us)
Ran 2 tests.  PASS: 2  FAIL: 0
[2573/3360] Running hermetic test libc.test.src.stdbit.stdc_first_leading_zero_uc_test.__hermetic__
[==========] Running 2 tests from 1 test suite.
[ RUN      ] LlvmLibcStdcFirstLeadingZeroUcTest.ALL
[       OK ] LlvmLibcStdcFirstLeadingZeroUcTest.ALL (2 us)
[ RUN      ] LlvmLibcStdcFirstLeadingZeroUcTest.ZeroHot
[       OK ] LlvmLibcStdcFirstLeadingZeroUcTest.ZeroHot (1 us)
Ran 2 tests.  PASS: 2  FAIL: 0

```

</details>

https://github.com/llvm/llvm-project/pull/186664