Investigate Node 20 regression report for Scope/XML plugin validation tests (no code change required)

[Copilot]

The issue reported two tests hanging/failing on Node 20 and a ~2x test slowdown. In the current branch state, that behavior is not reproducible: both named tests pass on Node 16/18/20, and Node 20 is not slower.

• Problem scope

  • Reported failures:
    • Scope -> Validate -> Emits validation events
    • XmlFile -> Transform Plugins -> Calls XML file validation plugins
  • Reported performance concern: test runtime significantly worse on Node 20.

• What changed in this PR

  • Added a cross-version verification pass for Node 16, 18, and 20 against current source state.
  • Confirmed the two reported tests are green under Node 20.
  • Confirmed runtime trend does not show Node 20 regression in current code (Node 20 is slightly faster than older versions in this environment).
  • No repository source/test code changes were required based on current findings.

• Current-state evidence snippet

  Node 16: TEST_TIME=0:23.60, 2910 passing
  Node 18: TEST_TIME=0:21.37, 2910 passing
  Node 20: TEST_TIME=0:20.02, 2910 passing
  

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• iojs.org
  • Triggering command: /usr/bin/curl curl -q --fail --compressed -L -s REDACTED -o - (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)