Test IMM#invalidateInput()

This CL adds test cases for IMM#invalidateInput() [1].

 [1]: I3161755779080f98bcef0e47dd0c5247d8a3a256

Bug: 203086369
Test: atest -c CtsInputMethodTestCases:InputMethodStartInputLifecycleTest
Change-Id: If4ec69f7688e3fdd3f5427f8543a4b2bc8d649b4
1 file changed