[Driver][test] Test intended target only
6fe7de90b9e4e466a5c2baadafd5f72d3203651d changed GNU toolchain,
and added new RUN line to test expected behavior.
The change is for GNU toolchain only, so this will fail other toolchain,
Update the test with -target to test GNU tool chain only.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D99901