frameworks/base: Protecting views from (bad) MotionEvents

When handling MotionEvents, the method findPointerIndex can return -1
if the current pointer id can't be translated to a pointer index.
Several views are not handling this, which will lead to an
out-of-index crash.

CRs-Fixed: 275381

Change-Id: Ica4446e4eb18ffb26de92b44465c249f230719f1