Regression: 'number instanceof EventEmitter' is true on main (test_gap_10556_instanceof_native_emitter fails) #11261

Regression on main: test-files/test_gap_10556_instanceof_native_emitter.ts fails on main 410b7fa10. It prints number instanceof EventEmitter: true; Node prints false.

The test passed on an older main earlier on 2026-09-24. Found during the A/B for #11253, where it failed identically on both arms (main and the branch), so #11253 did not cause it.

Needs a bisect between the last passing main and 410b7fa10. Candidates are recent instanceof or EventEmitter changes; the net listener binding in #11251 is not merged, so it isn't one of them.