repeat y for yuy2 so that unittests that check the 2nd y on odd widths will match the C and SIMD.  The C code duplicates the last Y.
repeat y for yuy2 so that unittests that check the 2nd y on odd widths will match the C and SIMD.  The C code duplicates the last Y.

R=harryjin@google.com
BUG=libyuv:455

Review URL: https://webrtc-codereview.appspot.com/50249004.

lyx2014/libyuv_free,lyx2014/yuv,lemenkov/libyuv,lyx2014/yuv,lyx2014/yuv,disigma/yuv,lyx2014/libyuv_free,lemenkov/libyuv,lyx2014/yuv,lyx2014/libyuv_free,lemenkov/libyuv,disigma/yuv,yarrcc/libyuv-ios,lemenkov/libyuv,lyx2014/libyuv_free,yarrcc/libyuv-ios,yarrcc/libyuv-ios,yarrcc/libyuv-ios,disigma/yuv