Make ImePerfTest wait for animation end

In show/hide ImePerfTests we waited for animationStart, however, it also
makes sense to wait for animation end to prevent overlapping and
avoiding reporting incorrect stats.
Fix: 191915803
Test: atest ImePerfTests

Change-Id: I7ef40db249afecc64b6a2418ff1ed7f90ccb4515
1 file changed