[llvm] [X86] With large code model, put functions into .ltext with large section flag (PR #73037)

[via llvm-commits]

lhames wrote:

@aeubanks JIT clients can look up sections by name (and we don't really give them a more structured way to identify sections) so it's possible that some clients are hard-coding searches for `.text`. As far as I know no in-tree code does that though. The risk seems low, and the fix is easy. I think it's reasonable to leave this in-tree and see what (if anything) shakes out.

https://github.com/llvm/llvm-project/pull/73037