[lld] [lld][MachO] Add initializer and +load roots to temporal BP sorting (PR #212110)

[Karim Alweheshy via llvm-commits]

karim-alweheshy wrote:

@ellishg @alx32, could you review this Mach-O BP change when convenient? It adds opt-in pre-main roots for initializer functions and Objective-C +load implementations, with reduced regressions for absolute/relative metadata, relocation addends, ICF canonicalization, and final ordering. The refreshed head is cleanly mergeable and the full upstream pre-merge matrix is green.

https://github.com/llvm/llvm-project/pull/212110