The file is getting too large and it's hard to find things. It won't scale.

Note: renaming golden tests will invalidate their history.

Possible solutions:

1. Just break up aiks_unittests.cc based on categories (ex aiks_clipping_unittests.cc, aiks_gradient_unittests.cc)
2. Completely get rid of aiks_unittests and allow any unittests file to be able to do the same thing so we could mix unittests and golden image tests in a file like conical_gradient_contents_unittests.cc