Optimize apply_temporal_filter function
Optimize apply_temporal_filter function

This patch optimized apply_temporal_filter function. The diff^2 for each
pixel in the 16x16 block is calculated once beforehand, so that we don't
calculate it multiple times while evaluating a pixel's neighbors. This
would speed up the function.

Change-Id: Ibdb8b041f317fd6df198950e2acf9cfcde26860d

webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx