Collapse code paths for single- and multi-input kernels.

This patch simplifies the RenderScript driver and CPU reference implementation
by removing the distinction between sing- and multi-input kernels in many
places.  The distinction is maintained in some places due to the need to
maintain backwards compatibility.  This permits the deletion of some functions
and struct members that are no longer needed.  Several related functions were
also cleaned up.

Change-Id: I77e4b155cc7ca1581b05bf901c70ae53a9ff0b12
25 files changed