Give some WebCore classes allocation heap identifiers
<rdar://problem/105334665>
Pull request: https://github.com/WebKit/WebKit/pull/9978
Pull request: https://github.com/WebKit/WebKit/pull/10422
Committed 260590@main (f07b7ad2599f): <https://commits.webkit.org/260590@main> Reviewed commits have been landed. Closing PR #10422 and removing active labels.