Wait for window animations to complete before injecting input for test

Some tests add windows that have animations and then inject input. The
inject input may occur before the windows are in their final position so
it causes test failures.
This change ensures that all windows that have pending animations
complete before proceeding to inject inputs for tests.

Bug: 122965081
Bug: 121122996
Bug: 123041491
Test: SearchView_CursorTest#testSuggestionSelection
Test: PopupMenuTest#testDismissalViaTouch
Test: ListPopupWindowTest
Change-Id: I648446be1e14d5101c0f8f97a0f157cde98b5aea