Make likelihood lit test less brittle
Jeremy Morse discovered an issue with the lit test introduced in D88363. The
test gives different results for Sony's -O1.
The test needs to run at -O1 otherwise the likelihood attribute will be
ignored. Instead of running all -O1 passes it only runs the lower-expect pass
which is needed to lower __builtin_expect.
Differential Revision: https://reviews.llvm.org/D89204