[test] Tweak driver test from r353917 and r353922 to pass with a nondefault CLANG_DEFAULT_LINKER

Force -fuse-ld=ld, as some other tests in the same file do.

Loosen the regex matching the linker tool name as well, as this
can end up being <triple>-ld in case such a named tool exists.

llvm-svn: 353946