[clang][Driver] Correct OpenBSD UBSAN options test

The RUN here was mising ":" and there was no check file passed
to FileCheck. This has been the case since this was originally added.

UBSAN is the only sanitizer that is available for OpenBSD,
but it does not add a simple "-fsanitize=undefined" instead
it adds a bunch of smaller options. So check for those like
the existing tests do.