Improve PackageWatchdogTest#raiseFatalFailure

Since calls to raiseFatalFailure are always followed by
TestLooper#dispatchAll, we can combine them to reduce boilerplate code.

Bug: 140691154
Test: atest PackageWatchdogTest
Change-Id: I0ea23dc132f2ad26ced1119bc5278bc5d876949c
1 file changed