Reland "Respect full precision for RGB16 PNGs" (part 1)

This is just the new test images.

I'm relanding this in pieces to try to bisect a
strange MSAN error.

Original CL:
https://skia-review.googlesource.com/c/7085/

BUG=skia:

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD,Build-Ubuntu-Clang-x86_64-Release-Fast,Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-MSAN

Change-Id: Iec6b8cf52134992591651bf46bd6cd67d53fad52
Reviewed-on: https://skia-review.googlesource.com/7201
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
2 files changed