[clang] [clang][NFC] Move more functions from `Sema` to `SemaObjC` (PR #97172)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

While I think these changes are defensible, I think I would prefer to *not* move all of the blocks logic into SemaObjC, but I'd love to hear if @rjmccall agrees with my rationale and conclusion.

Blocks are largely an Objective-C feature, so putting them together makes sense from that perspective. But Blocks are a C and C++ language extension that Objective-C and Objective-C++ pick up automatically; we even document it as such in https://clang.llvm.org/docs/BlockLanguageSpec.html I think that placing blocks into Objective-C semantics makes that point less clear, but it is an important distinction. For example, WG21 is now looking at the syntax used for reflection because it was pointed out that the proposed syntax conflicts with a conforming extension in C++ in a way that would be hard for us to support.

WDYT?

https://github.com/llvm/llvm-project/pull/97172