~3-4% faster lossless encoding

by re-arranging some code from SkipRepeatedPixel()

Change-Id: I6c1fd7cd9af22cd9be4234217ff67d7b94f44137
Merge "~3-4% faster lossless encoding"
histogram.c: reindent after b33e8a0

b33e8a0 Refactor code for HistogramCombine.

Change-Id: Ia1b4b545c5f4e29cc897339df2b58f18f83c15b3