Since the test suite has moved to WPT we're importing the manual tests too.
This causes that we've several "caret-color" tests duplicated,
as initially we imported some of them manually under "editing/caret/".

It'd be nice to avoid this duplication, but we had some issues on the first try,
Because PNGs are not generated for the manual tests under "external/wpt/".

More detailed info on: https://codereview.chromium.org/2833483002/