Ensure the primitive subregion is clipped to the effect geometry. The Filter/FilterEffect is set up to work this way for long time. This new test was used to verify the geometry of the GraphicsContext filters are working correctly.
<rdar://problem/102775394>
Pull request: https://github.com/WebKit/WebKit/pull/6926
Committed 257158@main (68a960c37445): <https://commits.webkit.org/257158@main> Reviewed commits have been landed. Closing PR #6926 and removing active labels.