Remove expectedFailureFreeBSD from passing test

ExprCommandWithTimeoutsTestCase::expectedFailureFreeBSD

This test passes locally but was marked XFAIL due to failures on the
FreeBSD buildbot. That buildbot has been retired as it was overloaded,
and we will investigate again if this fails once a new buildbot is in
place.

llvm.org/pr19605

llvm-svn: 247799