[lld-macho]Limit "cannot-export-hidden-symbol" warnings to only 3 to avoid crowding logs.

Details:
We often use wildcard symbols in the exported_symbols list, and sometimes they match autohide symbols, which triggers these "cannot export hidden symbols" warnings that can be a bit noisy.
It'd be more user-friendly if LLD could truncate these.

Differential Revision: https://reviews.llvm.org/D159095