[libc-commits] [libc] [libc][NFC] Rename LIBC_COMPILER_HAS_FLOAT128 to LIBC_HAS_FLOAT128 for consistency (PR #81870)

[Nick Desaulniers via libc-commits]

https://github.com/nickdesaulniers requested changes to this pull request.

It looks like we use `LIBC_COMPILER_HAS_*` for:
1. `FLOAT128`
2. `C23_FLOAT16`
3. `FLOAT128_EXTENSION`
4. `HAS_FLOAT128`

I can appreciate making the macro name more concise, but:
1. 

https://github.com/llvm/llvm-project/pull/81870