[lld] [lld/ELF] Warn on conflicting SHF_X86_64_LARGE flag (PR #72335)

[Reid Kleckner via llvm-commits]

rnk wrote:

We may actually want to consider an LLD warning suppression mechanism. LLD COFF and MSVC link.exe have a warning for mismatched section flags, and we should do the same for LLD. Typically, taking the union of R-- and RW- is OK, but merging RW- and R-X should be a warning/error, if it isn't already.

https://github.com/llvm/llvm-project/pull/72335