Reset IME show request when hide is requested

If there was a pending IME show post layout, reset it when IME is
requested to be hidden.

Fix: 142705233
Test: Manually tested using Google keep:
      1. Launch Google Keep and tap on search
      2. New search activity will launch with IME shown
      3. Press back on titlebar
      4. Keep app requests IME again (bad behavior) and then
         requests to hide it.
      5. verified that show request is reset.

Change-Id: I79bebcbdb1a56e42b196e158f1d015ac64bf78cf