[clang] [Clang] Remove NetBSD/i386 workaround for FP eval method with older versions (PR #74025)

[Simon Pilgrim via cfe-commits]

RKSimon wrote:

This should be documented in the release notes in case somebody was still building for such an old netbsd. Should we emit any compile warnings/errors when building for this triple?

https://github.com/llvm/llvm-project/pull/74025