Add a test to verify IME visibility after device unlocked.

As CL[1] to fix IME will shown when the dialog's Editor focus been cleared
after device screen-off.

Add a test to verify IME should invisible when focusing back to dialog
after device unlocked.

[1]: I37ae6e30d1de581ba15131c2a90396b3a522a4d6

Bug: 161506356
Test: atest KeyboardVisibilityControlTest#\
      testImeVisibilityWhenEditorInDialogClearedFocusAfterUnlocked

Change-Id: I2b1193f541933380fc97d83aee2da1e9d5f0faa9
1 file changed