avert 2500ms wait in InputMethodManager

When dispatching input events to the main thread, the event is
handled directly rather than queued. If we have a timeout waiting for
the event to happen, it has to be registered before we call the
dispatcher, otherwise we'll wait for the timeout even though the event
has already been handled.

Bug: 6734044
Change-Id: I6826163dbc6133b385cf1076bb077fb4e82870a1