SPIRV-Headers recently fixed the capability dependency for SampleMask. It depends on Shader, not SampleRateShading
The SPIR-V core grammar file in a recent SPIRV-Headers applied the fix from Rev 7 of SPV_KHR_16bit_storage: FPRoundingMode enums are now enabled by the capabilities introduced by that extension. Update the SPIRV-Tools tests accordingly.
Also posfixing test files with `_test' to make it more clear.
