Create only single StatFileWatcher through node

[sheetalkamat]

To avoid getting MaxListenersExceededWarning on the stat watcher that is shared in node for a filename use it only once and manage callbacks instead.
Fixes #28690

[orta]

Looks good, it strives to make sure that if files overlap with multiple projects then we never create more than one watcher per file to save on memory 👍