Let's split this from bug #220117. We should crash if the application tries to mount / or /home or $HOME in the sandbox. We cannot prevent apps from allowlisting whatever they wish, but if they want to be stupid they should have to try somewhat harder than that.
Pull request: https://github.com/WebKit/WebKit/pull/8330
Committed 259309@main (4b0c2332b9a6): <https://commits.webkit.org/259309@main> Reviewed commits have been landed. Closing PR #8330 and removing active labels.