[Flight] Don't track Promise stack if there's no owner (#33734)

This is a compromise because there can be a lot of Promise instances
created. They're useful because they generally provide a better stack
when batching/pooled connections are used.

This restores stack collection for I/O nodes so we have something to
fallback on if there's no owner.

That way we can at least get a name or something out of I/O that was
spawned outside a render but mostly avoids collecting starting I/O
outside of render.