In order to integrate DOMTimers with HTML5 event loop, make alignedFireTime external to Timer class.
Pull request: https://github.com/WebKit/WebKit/pull/16540
Committed 266751@main (cf15c62f09b9): <https://commits.webkit.org/266751@main> Reviewed commits have been landed. Closing PR #16540 and removing active labels.
<rdar://problem/113665907>