av1: Allow odd width/height for YUV420

Allow odd width/height values for the gav1 software decoder.

Notes:
* We already allocate the graphic block with a stride that is a
  multiple of 16, that behavior is retained.
* We also allocate the graphic buffer with a height alignment of 2 (this
  change is needed because fetchGraphicBlock fails for odd height
  values.
* We set the correct "crop" value in createGraphicBuffer() which will
  handle odd width/height appropriately.
* This change also enables decoding of AVIF images that have odd
  dimensions.

This CL contains changes to the non-mainline files.

Test: CtsMediaTestCases still pass
Bug: 175243729
Change-Id: Ia47fa8f9936873542a6e7f46e2f704b273a69b5c