[clang] [clang][CodeGen] Remove "unsafe-fp-math" attribute support (PR #162779)

[Andy Kaylor via cfe-commits]

andykaylor wrote:

I'm very happy to see progress being made on transitioning away from the function attributes for fast-math control. That said, it looks like there are still some things in the PowerPC ISel code that were using this attribute (by way of the UnsafeFPMath setting in TargetOptions).

Do you have plans to remove the backend handling of this attribute?

https://github.com/llvm/llvm-project/pull/162779