Revert "[Driver] MinGW: Remove custom linker detection"

This reverts rL313102 because it still fails some build bot tests.

On many linux bots it fails with the following error.
error: invalid linker name in argument '-fuse-ld=lld'
and on some windows bots also because there is no ld.lld.exe
lld-link.exe: warning: ignoring unknown argument: -fuse-ld=lld

llvm-svn: 313104