Add P016 and P010 examples to wacky_yuv_formats GM

These formats are for HDR YUV.

This CL also adds partial support for Y416 but, without Ganesh support for RGBA_16161616, it can't be displayed.

Change-Id: I4218a104f2935d1395ee6c7c6792105092e1eeb3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/214220
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

Author: rphilli