Detect outdated pending post KeyPress handler

modules/ve/ce/ve.ce.Surface.js
* Schedule the post-keypress async handler in a way that can be cancelled.
* Cancel it and run the handler immediately if another key event happens.

Bug: 53079
Change-Id: If139ff3230c10caa616743f71659c4606d290310
Merge "Detect outdated pending post KeyPress handler"