[lld] [llvm] [lld][COFF] Restore `lto-embed-bitcode` and `-fembed-bitcode` Bitcode Embedding Features (PR #188398)

[Haohai Wen via llvm-commits]

https://github.com/HaohaiWen commented:

This will always keep .llvmbc and .llvmcmd in the final binary if -fembed-bitcode is presented.
As I mentioned in the https://github.com/llvm/llvm-project/pull/150897#issuecomment-4122577303. Sometimes, we just want it exist in the object/bitcode but not in the final binary to avoid 2GB PE limitation.

https://github.com/llvm/llvm-project/pull/188398