[llvm] [LV] Add tests for missed scalarization opportunities. (PR #225508)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-mlir-rhel-clang` running on `ppc64le-mlir-rhel-test` while building `llvm` at step 4 "cmake-configure".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/129/builds/53469

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

```
Step 4 (cmake-configure) failure: cmake (failure) (timed out)
...
-- Performing Test THREAD_SAFETY_ATTRIBUTES -- success
-- Performing Test HAVE_CXX_FLAG_COVERAGE
-- Performing Test HAVE_CXX_FLAG_COVERAGE - Success
CMake Warning at /home/buildbots/llvm-external-buildbots/workers/ppc64le-mlir-rhel-test/ppc64le-mlir-rhel-clang-build/llvm-project/third-party/benchmark/CMakeLists.txt:329 (message):
  Using std::regex with exceptions disabled is not fully supported


-- Performing Test STEADY_CLOCK -- success
-- Performing Test PTHREAD_AFFINITY -- failed
-- Configuring done (682.1s)
command timed out: 1200 seconds without output running [b'cmake', b'-DLLVM_TARGETS_TO_BUILD=PowerPC', b'-DLLVM_INSTALL_UTILS=ON', b'-DCMAKE_CXX_STANDARD=17', b'-DLLVM_ENABLE_PROJECTS=mlir', b'-DLLVM_LIT_ARGS=-vj 256', b'-DCMAKE_C_COMPILER_LAUNCHER=ccache', b'-DCMAKE_CXX_COMPILER_LAUNCHER=ccache', b'-DCMAKE_BUILD_TYPE=Release', b'-DLLVM_ENABLE_ASSERTIONS=ON', b'-GNinja', b'../llvm-project/llvm'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1883.821540

```

</details>

https://github.com/llvm/llvm-project/pull/225508