Define the Mach bootstrap filter to be used after the WebContent process has finished launching.
Pull request: https://github.com/WebKit/WebKit/pull/1775
<rdar://problem/95873385>
Committed 251888@main (8bc5eb48b7cd): <https://commits.webkit.org/251888@main> Reviewed commits have been landed. Closing PR #1775 and removing active labels.