Apply clang-format to fix jpeg if() for lint fix.
Change comments about 4th pixel for open source compliance.
Rename UVToVU to SwapUV for consistency with MergeUV.

BUG=b/135532289, b/136515133

Change-Id: I9ce377c57b1d4d8f8b373c4cb44cd3f836300f79
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/1685936Reviewed-by: Chong Zhang <chz@google.com>
Commit-Queue: Frank Barchard <fbarchard@chromium.org>