Should toRGB() tests in css/css-typed-om/stylevalue-subclasses/cssRGB.html be removed?

`toRGB()` was replaced with a more generic method in https://github.com/w3c/css-houdini-drafts/issues/1036, and later removed in https://github.com/w3c/css-houdini-drafts/issues/1070.

The methods are not in the standard any more, and future implementations will not support them. The tests should probably be removed?