Check that orientation is still absent after reloading Exif

[radarhere]

Suggestions for python-pillow#6463

1. I've noticed that the tests in the PR pass even without the change to ImageOps. You've done the right thing, the problem is that Once exif data is parsed, do not reload unless it changes python-pillow/Pillow#6335 means that the "XML:com.adobe.xmp" data isn't checked after exif_transpose is run. So I've updated the tests to run _reload_exif(), so that it is checked.
2. I created a test image using one of our existing test images and exiftool -orientation#=3 -exif= color_snakes.png. By having an orientation of 3, it allowed the test code to be a bit simpler, since the orientations match.