We seem to be invalidating less and some issues with overflowing Cocoa
native widget themes have appeared. We've worked around these issues
elsewhere, e.g. by getting rid of scrollbars, so I'm doing it here too.
The test 745025-1.html dynamically updates a print reftest, which seems
to cause problems on Mac with the page shadow drawing. This is not
important and is already a known intermittent failure.
