Import WPT fullscreen tests from upstream.
Pull request: https://github.com/WebKit/WebKit/pull/5055
*** Bug 246066 has been marked as a duplicate of this bug. ***
rdar://44505169
Committed 255217@main (584c3ccd45e6): <https://commits.webkit.org/255217@main> Reviewed commits have been landed. Closing PR #5055 and removing active labels.