Statsd CTS: fix procstate tests

Testing Foreground and TopSleeping requires that ActivityManager know
that the screen state has changed before the app launches. On some
devices it is a little slow, which was causing the test to fail. This
fixes that.

Change-Id: I3282b6fd05bce49af329152d587f54e303a30870
Fixes: 75280342
Test: run cts-dev -m CtsStatsdHostTestCases -t android.cts.statsd.atom.ProcStateAtomTests
1 file changed