Do amortized clean up in WeakHashSet, similarly to what we already do in WeakHashMap.
Pull request: https://github.com/WebKit/WebKit/pull/6331
Committed 256541@main (06391ab46e02): <https://commits.webkit.org/256541@main> Reviewed commits have been landed. Closing PR #6331 and removing active labels.
<rdar://problem/102201010>
Committed 252432.1032@safari-7614-branch (c8b8b96aa796): <https://commits.webkit.org/252432.1032@safari-7614-branch> Reviewed commits have been landed. Closing PR #291 and removing active labels.