[llvm] [MIPS][float] Fixed SingleFloat codegen on N32/N64 targets (PR #140575)

[Davide Mor via llvm-commits]

Tazdevil971 wrote:

Ok I changed a couple of things:

- Added new test cases for the assembly register constraint logic
- Renamed tests to be more consistent

I still haven't merged all of the variants of the calling conventions tests as I'm not sure it's a good idea, I'll first try on another branch and see if it could work.

https://github.com/llvm/llvm-project/pull/140575