[lld] [LLD][COFF] Deduplicate common chunks when linking COFF files. (PR #162553)

[Reid Kleckner via llvm-commits]

rnk wrote:

Thanks for the fix, it's somewhat hard for me to believe that LLD was just keeping common symbols around since forever. I guess most of our usage has been focused on C++ usages, with very few common symbols.

https://github.com/llvm/llvm-project/pull/162553