Uncouple EventLoopTimer and SuspendableTimer so that we don't need ScriptExecutionContext for scheduling a (repeating) task on the event loop.
Pull request: https://github.com/WebKit/WebKit/pull/16456
Committed 266699@main (73fb990c113c): <https://commits.webkit.org/266699@main> Reviewed commits have been landed. Closing PR #16456 and removing active labels.
<rdar://problem/113586040>