[llvm] Enable logf128 constant folding for AArch64 (PR #96287)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

I don't understand how this works.  logf128 is defined to take a _Float128, by the C standard.  long double is not _Float128, and is not compatible with _Float128.  Therefore, it should not be possible to implicitly convert a `_Float128(*)(_Float128)` to `long double (*)(long double)`.

https://github.com/llvm/llvm-project/pull/96287