Optimize WTF::compactMap() by having it initialize vector capacity and rely on Vector's unsafeAppendWithoutCapacityCheck(), similarly to WTF::map().
Pull request: https://github.com/WebKit/WebKit/pull/19907
Committed 270194@main (c1279eabfb21): <https://commits.webkit.org/270194@main> Reviewed commits have been landed. Closing PR #19907 and removing active labels.
<rdar://problem/117915643>