[lld] [lld] Merge GOT entries for symbols that have been ICFed (PR #131630)

[Pranav Kant via llvm-commits]

pranavk wrote:

If both are same kind of symbols, I agree. But now I look closely at the pauth test failure, we need to handle function symbols and data symbols differently as what key we end up using in pauth depends on whether it's a func or not (IA vs DA).

https://github.com/llvm/llvm-project/pull/131630