b/3307761 Clean up the flag mIsHandlingMultiTouch.
b/3307761 Clean up the flag mIsHandlingMultiTouch.

The flag mIsHandlingMultiTouch was used to remove the out of order
touchMove events. After the fix b/3307761, it is no more needed.

Change-Id: I4d03131e2a22c53cc79c4105e39f078f1bea88ca

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base