pixel: remove sad_16, sad_x3_16 and sad_x4_16

We have assembly coverage for everything but sad_16x12; which I've put on the
top of our TODO list.
asm: created comman asm macro for pixel_sad_32xN functions
asm: assembly code for pixel_sad_32x8
asm: assembly code for pixel_sad_32x24
asm: assembly code for pixel_sad_32x32
asm: assembly code for pixel_sad_32x16
asm: assembly code for pixel_sad_32x64
asm: assembly code for pixel_sad_8x32
testbench: upgrade for check_IPFilter_primitive, don't pass wrong (width, height, stride) to asm
pixel: remove sad_8, sad_x3_8, sad_x4_8 intrinsic functions