Add syscall required by ASAN builds.
<rdar://problem/117027010>
Pull request: https://github.com/WebKit/WebKit/pull/19119
Committed 269373@main (9155229feaff): <https://commits.webkit.org/269373@main> Reviewed commits have been landed. Closing PR #19119 and removing active labels.
Re-opened since this is blocked by bug 263267