Fix PopupMenuTest#testHoverSelectsMenuItem failure

The `Instrumentation.sendPointerSync` used
INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT that would not wait for the
input event to finish being handled by the application.
This CL Replaced it by `CtsMouseUtil` so we can guarantee the
application could handle the event before it return.

Bug: 228201593
Test: atest PopupMenuTest
Change-Id: I5d14b92d774a17992aec8f026847f26b21b00556
1 file changed