[lld][COFF] Restore `lto-embed-bitcode` and `-fembed-bitcode` Bitcode Embedding Features (#188398)
Removes the patches introduced by #150897 which broke LTO embed
documented features for creating whole-program-bitcode representations
of executables, used in production analysis/rewriting toolsets. This was
a documented feature available up until 21.1.8 broken by 22.x release.
This previously allowed the users to have a whole-program-bitcode
section `.llvmbc` embedded inside of the final executable.