Fix array index out of bounds exception problem.

The getPrimaryPointerId method may return the  INVALID_POINTER_ID(-1) value and result to  array index out of bounds exception.The crash log:
java.lang.ArrayIndexOutOfBoundsException: length=32; index=-1
at com.android.server.accessibility.gestures.TouchState$ReceivedPointerTracker.getReceivedPointerDownX(TouchState.java:482)
at com.android.server.accessibility.gestures.TouchExplorer.handleActionMoveStateTouchExploring(TouchExplorer.java:910)
.....

Test: monkey test
Flag: EXEMPT bugfix
Bug: 399557645
Change-Id: Ib0b14471953d8f78cf98122dd868be8b80059a75