[OpenMP][omptest] Adopt omptest installation guard into scripts

[mhalk]

Enable installation of omptest for 'project' and 'openmp' components by default.
See: llvm/llvm-project#155433

Motivation

Installation of omptests is going to be guarded but a subset of tests depends on it.
Hence, we want to install the corresponding components of omptest.

Technical Details

Added -DLIBOMPTEST_INSTALL_COMPONENTS=ON to the common CMake options.

Test Plan

Verified presence of installation manually with and without the patch.

Test Result

Without the patch no files matching *omptest* are present in the AOMP installation directory.
With the patch each configuration has a corresponding omptest installation.

[jplehr]

lgtm

Do we need to land llvm-project change first or is this option simply ignored w/o the llvm patch?

[mhalk]

Do we need to land llvm-project change first or is this option simply ignored w/o the llvm patch?

No, the option is "ignored".
That is, there will be a corresponding warning, e.g. for build_openmp.sh:

CMake Warning:
  Manually-specified variables were not used by the project:

    DEVICELIBS_ROOT
    LIBOMPTARGET_AMDGCN_GFXLIST
    LIBOMPTARGET_ENABLE_DEBUG
    LIBOMPTARGET_LLVM_INCLUDE_DIRS
    LIBOMPTARGET_NVPTX_BC_LINKER
    LIBOMPTARGET_NVPTX_COMPUTE_CAPABILITIES
    LIBOMPTARGET_NVPTX_CUDA_COMPILER
    LIBOMPTARGET_NVPTX_ENABLE_BCLIB
    LIBOMPTEST_INSTALL_COMPONENTS           # Patch adds this line while upstream PR still unmerged
    LLVM_DIR
    LLVM_ENABLE_PER_TARGET_RUNTIME_DIR
    LLVM_LIBDIR_SUFFIX
    LLVM_MAIN_INCLUDE_DIR