nit: more spotbugs fixes

[jasonk000]

Fix four spotbugs issues:

1. Node.attributeName was never written to, always stayed null -> remove the attributeName field, which means decorateWithAttributeName is never used (all class private), and the codepath can be cleaned up.

2. LeakHunterQuery reuses the Map.Entry object which might be reused -> reconstruct a new Map Entry.

   • the Map.entry() constructor requires Java9+

3. resolveIsDaemon returns Boolean, which might be auto-unboxed to boolean by caller and trigger a NPE -> Annotating @CheckForNulls ensures call site is validated to check that it is null before using.

4. Value stored to tt1 which was never read -> Shuffle things around so scope is more natural/clear.

[jasonk000]

brings us from 394 -> 390

[krumts]

LGTM