Add option to skip kernel build in op_test build_mha.sh

[Micky774]

Motivation

Often times we'll use the generated {f, b}wd.exe programs to isolate specific kernels and validate TE's AITER integration. In doing so, we usually prefer to use existing pre-built libmha_{f, b}wd.so libraries. This addition makes it so we can directly skip building the libraries while still easily building {f, b}wd.exe.

Technical Details

Adds an option to skip running compile.py in build_mha.sh by setting AITER_TEST_SKIP_BUILD=1. It is not set by default, hence this change is backwards compatible.

Test Plan

N/A

Test Result

N/A

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[Copilot]

Pull request overview

Adds a build-time switch for the MHA op test harness to optionally skip compiling the MHA kernel shared libraries while still producing the {f,b}wd.exe benchmarks, supporting workflows that rely on prebuilt libmha_{f,b}wd.so.

Changes:

• Add AITER_TEST_SKIP_BUILD=1 option to skip running compile.py in build_mha.sh.
• Continue to the existing link steps to produce fwd.exe / bwd.exe even when the compile step is skipped.

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[Copilot]

python3 compile.py is invoked via a relative path before SCRIPT_DIR is computed. If this script is run from outside op_tests/cpp/mha/, the build step will fail because compile.py won’t be found. Consider computing SCRIPT_DIR at the top and invoking python3 "$SCRIPT_DIR/compile.py" --api="$FMA_API" (also quoting $FMA_API to avoid word-splitting).

[Copilot]

When AITER_TEST_SKIP_BUILD=1, the script proceeds to linking but doesn’t validate that the expected prebuilt libraries exist in $SCRIPT_DIR (e.g., libmha_fwd.so / libmha_bwd.so). Skipping the check can lead to a confusing hipcc: cannot find -lmha_* error; consider checking for the required .so files based on FMA_API and exiting with a clear message if they’re missing.