Stop using Vector::unsafeAppendWithoutCapacityCheck() in MarkedSpaceInlines.h.
Pull request: https://github.com/WebKit/WebKit/pull/20587
Committed 270852@main (4b9b56921199): <https://commits.webkit.org/270852@main> Reviewed commits have been landed. Closing PR #20587 and removing active labels.
<rdar://problem/118534676>