Based on telemetry, block unused mach syscalls in the WebContent process sandbox on macOS.
<rdar://problem/117450710>
Pull request: https://github.com/WebKit/WebKit/pull/19523
Committed 269814@main (601d619de658): <https://commits.webkit.org/269814@main> Reviewed commits have been landed. Closing PR #19523 and removing active labels.