S32A_Blend_BlitRow32: for ARM without NEON
S32A_Blend_BlitRow32: for ARM without NEON

The S32A_Blend_BlitRow32 function was written and unrolled in ARM
assembly to improve the rendering performance on ARM cores lacking
NEON.

Added in SkBlitRow_opts_arm.cpp.

Performance improvement about ~18% on micro benchmarking.

Patch-by: Vassillis

git-svn-id: e8541e15acce502a64c929015570ad1648e548cd@598 2bbb7eff-a529-9590-31e7-b0007b416f81

MatChung/color-emoji.skia,Hankuo/color-emoji.skia,MatChung/color-emoji.skia,MatChung/color-emoji.skia,Frankie-666/color-emoji.skia,Hankuo/color-emoji.skia,mrobinson/skia,metajack/skia,Hankuo/color-emoji.skia,hbwhlklive/color-emoji.skia,hbwhlklive/color-emoji.skia,mrobinson/skia,Cue/skia,metajack/skia,MatChung/color-emoji.skia,MatChung/color-emoji.skia,Frankie-666/color-emoji.skia,Frankie-666/color-emoji.skia,MatChung/color-emoji.skia,mrobinson/skia,hbwhlklive/color-emoji.skia,Frankie-666/color-emoji.skia,mrobinson/skia,Frankie-666/color-emoji.skia,Cue/skia,metajack/skia,hbwhlklive/color-emoji.skia,Hankuo/color-emoji.skia,Hankuo/color-emoji.skia,mrobinson/skia,Cue/skia,metajack/skia,Cue/skia,Hankuo/color-emoji.skia,hbwhlklive/color-emoji.skia,hbwhlklive/color-emoji.skia,Frankie-666/color-emoji.skia