[llvm] [X86] Consistently use f128 libcalls (PR #142386)

[Nikita Popov via llvm-commits]

nikic wrote:

This is using glibcs native f128 support, not libquadmath. See https://gcc.godbolt.org/z/fWeh3a98Y (for both x86-64 and x86-32). If you use the `*l` libcalls instead you get extra tfxf conversions.

https://github.com/llvm/llvm-project/pull/142386