[llvm] [MC] Set HasAggressiveSymbolFolding to true (PR #84242)

[Fangrui Song via llvm-commits]

MaskRay wrote:

True `HasAggressiveSymbolFolding` is related to Mach-O assembler limitation. The code has been refactored multiple times. One is 44bbe36de66b44f7c9b7355709b62609886e287a (2010).

Setting `HasAggressiveSymbolFolding` to false will break 3 `check-llvm-mc` tests.

That said, some Mach-O specific variables in `MCAsmInfo.h`  can be cleaned up.


https://github.com/llvm/llvm-project/pull/84242