specialization constant tests aren't very complete

Nothing tests any of the failure paths from this.

a test to create an SPIR-V shader, and try and use incorrect sized arguments, incorrect ids,

The issue names no files or existing test entry points, so first locate the specialization constant tests and the SPIR-V shader setup. Add coverage for failure paths involving incorrectly sized arguments and incorrect IDs, then verify those tests fail for the intended invalid inputs.

Written by the indexing model from the issue text.