DriverPipeline: Ensure -globalopt is passed to LLVM opt

While -O1 and -O2 both include -globalopt, the order in which the passes are
run means that aliases aren't resolved which then causes llc to fall over.
See GHC bug #8855.

Signed-off-by: Austin Seipp <austin@well-typed.com>
(cherry picked from commit b84b5da4)