ABGR output is implemented using the same source code as ARGB, by swapping
the u and v and supplying the mirrored conversion matrix.
ABGR format (RGBA in memory) is popular on Android.

Bug: libyuv:751
Test: H010ToABGR, I010ToABGR and I010ToARGB unittests

Change-Id: I0b5103628c58dcb22a6442c03814d4d5972e0339
Reviewed-on: https://chromium-review.googlesource.com/852985
Commit-Queue: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Frank Barchard <fbarchard@chromium.org>