[RenderScript] Implement APIs for better multi-frame process support.

Bug: 23535524

 Two APIs added for multiframe processing:
 - createAllocations(...): To create an array of Allocations sharing the
   same Type and Usage. For USAGE_IO_INPUT Allocations, they also share
   the same BufferQueue.
 - getTimeStamp(): API to retrieve the time stamp associated with the
   most recent buffer.

Change-Id: I6b7b35d7dca5e87ee2f3db2ee17cb9cf824bcfe1