Use tighter typing for value returned by JSDOMWindowBase::scriptExecutionContext().
Pull request: https://github.com/WebKit/WebKit/pull/10987
Committed 261145@main (34d9c5fdefdb): <https://commits.webkit.org/261145@main> Reviewed commits have been landed. Closing PR #10987 and removing active labels.
<rdar://problem/106196387>