[Build] Fix Windows ARM64 CUDA plugin build (#31617)
The Windows ARM64 CUDA plugin packaging job passes `--skip_tests`, but
that option skips test execution only; it does not disable generation
and compilation of unit-test targets. Because
`onnxruntime_BUILD_UNIT_TESTS` defaults to ON, the job still builds
`onnxruntime_mlas_test`.
In the failing CI run, the MLAS library itself compiled and linked
successfully, including `sqnbitgemm_kernel_avx512_2bit.cpp`. The later
failure was an ARM64 MSVC compiler crash while compiling the unused
`onnxruntime_mlas_test` target: `CL.exe` exited with code `57005`
(`0xDEAD`) during `test_sqnbitgemm_2bit.cpp`.
This change sets `onnxruntime_BUILD_UNIT_TESTS=OFF` only for the Windows
ARM64 CUDA plugin packaging job. The CUDA plugin and MLAS library are
still built, and the existing plugin binary verification remains
enabled; only unit-test targets that are not run by this packaging job
are excluded.
Note: A more complete fix is to split sqnbitgemm_kernel_avx512_2bit.cpp
into multiple files.
Validation:
- YAML parsed successfully.
- Confirmed the define is present only in the ARM64 CUDA plugin build
block.
- `git diff --check` passed.
- Windows ARM64 CI build remains to be verified by this PR.
