Defer tap outside stack until multiwindows

Taps outside of the stack boundary were causing the current app to
lose focus. This led to timeouts waiting for the app to respond.

Disabling the tap recognition keeps the focus from changing. It will
be reenabled for multiwindows.

Fixes bug 17721767.

Change-Id: Iad854b19979390e73b97239e489ad7ef82e03d47