[clang] [llvm] [PowerPC] Tune AIX shared library TLS model at function level by heuristic (PR #84132)

[Hubert Tong via cfe-commits]

https://github.com/hubert-reinterpretcast commented:

See inline comments for rationale re: scoping to LD -> IE only (and not performing IE -> LD).

https://github.com/llvm/llvm-project/pull/84132