Camera: make scale and crop test aspect ratio agnostic

Remove the AR_CHECKED special treatment and require all output
sizes to pass the aspect ratio check (a circle must not be
stretched). This enables testing on sensors of non-typical
aspect ratios.

Also added more documents on what the test is doing and refactor
to make it more readable.

Fix two other issues:
  - Scale RAW image back to original size (instead of 1/2 size
    returned by convert_capture_to_rgb by default) unconditionally
  - Do not apply distortion correction on "iter" images which
    are YUV/JPEG and already subject to HAL distortion correction

Bug: 152739464
Test: Pixel devices
Change-Id: I9dddf858459476ce28350aa02f9c0247190d83bd
1 file changed