Bug 1911531 - Forbid any WorkerRunnable execution in...

Bug 1911531 - Forbid any WorkerRunnable execution in WorkerPrivate::RunLoopNeverRan. r=dom-worker-reviewers,asuth a=RyanVM

This is a patch for uplift PreStartRunnable cleaning on the Worker thread for ESR128.
It includes the following fixes
[[ https://phabricator.services.mozilla.com/D213947 | bug 1894231 ]] introduces WorkerRunnable::mCleanPreStartDispatching instead of using WorkerPrivate raw pointer.
[[ https://phabricator.services.mozilla.com/D215601 | bug 1905337 ]] keeps dispatched PreStartRunnables in WorkerPrivate::mPreStartRunnables.
[[ https://phabricator.services.mozilla.com/D216379 | bug 1907383 ]] does not execute WorkerControlRunnable if Worker initialization fails
[[ https://phabricator.services.mozilla.com/D218619 | bug 1911531 ]] Ensures all dispatched runnables in Pending status are appended in WorkerPrivate::mPreStartRunnables.

Differential Revision: https://phabricator.services.mozilla.com/D217546