Fix spurious ANR occurence when MOTION batch event is not served by the InputTransporter

Sometimes Batch event of MOTION type is not processed by the Input Transporter
even though it is queued to the waitQueue-Responsible for ANR whenever any event
response does not come from the App. To fix this issue, one Boolean lock is added.
Thus InputTransporter wont ignore the Batch event.
Issue: https://code.google.com/p/android/issues/detail?id=41755

Change-Id: I3bb2eb4cf1f8ecdd1d04671c0e8205dee4ad3a6c