SPIR: Exit code mismatch for missing cl_khr_spir causes failure

[bananAshkar]

The SPIR test returns TEST_SKIPPED_ITSELF (-100) when cl_khr_spir is missing via REQUIRE_EXTENSION This is inconsistent with existing behavior where main() returns 0 when SPIR 1.2 is unsupported, so missing cl_khr_spir should be aligned to return success instead.

[bashbaug]

I think this is just a bug. The cl_khr_spir testing does not seem to be using the test harness like most other tests, so it's behaving differently.