Approving this because nothing screams of being wrong and I'm not uncomfortable with anything in this MR, but my knowledge of the low level bits of SM1 is pretty weak, so I can't really give an independent confirmation that we want these changes. But I have a general trust that Zeb knows what she's doing! :-)
Sanity-checking the code changes is always appreciated even if you have to trust that the functional change is correct :-)
1/4 and 4/4 were both things I came across while trying to get sm1 tests to work, so in a sense we already have tests for those, we just can't quite run them yet.
2/4 and 3/4 are things related to ps_1_*, which I think we originally dismissed as not worth implementing, on the basis that native doesn't support emitting them and implicitly promotes them to ps_2_*. But native d3dx9_31 does support emitting ps_1_*, and perhaps more importantly, we want to be able to test that our sm1 -> glsl/spirv translator can correctly handle those versions.