Original patch by Kyungwoo Lee <email@example.com>
Added test case for mllvm option.
My original idea was to test mllvm using the -time-passes option.
It turns out that lld-link does not perfom a full shutdown (and there is no -full-shutdown option available) when exiting.
So I opted for passing -debug-pass=Arguments and checking for the output string: "Pass Arguments:".