tests: Improvements for SM1 testing.
This is the first part of !608 (merged), which I decided to separate to ease review.
It consists of improvements to SM1 testing, mainly:
- Correctly passing int and bool uniforms as IEEE 754 floats to SM1 profiles.
- The introduction of the "only" qualifier to avoid abusing
[require]
blocks in case tests retrieve different results for different shader models. - Allowing some of the tests we already have for SM4/SM6 to run in SM1 after those improvements.