[DOM] Treat omitted Fragment Event listener options same as capture: false

[teamleaderleo]

Summary

FragmentInstance tracks its event listeners so they can be applied to children added later, and matches them by a normalized options identity. Omitted options currently normalize to a different identity than an explicit false or {capture: false}, even though both mean capture: false per the EventTarget contract, where listener identity is the tuple of type, callback, and capture flag. As a result, a listener added without an options argument cannot be removed with an explicit capture-false value (or the reverse).

This change normalizes omitted options to the same capture-false identity as false and {capture: false}. The first commit adds a test to the FragmentRef suite characterizing the current behavior; the second commit contains the fix and the updated assertions.

How did you test this change?

• added test characterizing the bug in the first commit

[dianatofficial]

Solid PR. Tests cover the important paths.

[github-actions]

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[eps1lon]

I rebased this onto main and split it into two commits: the first characterizes the current behavior, the second contains the fix and the updated assertions.

Two of the three issues were already fixed on main in the meantime: FragmentInstance.removeEventListener now returns early when the listener was never registered, before touching child listeners or the registry, and the existing FragmentRef suite already has a regression test for that case. What remains is the options identity issue: omitted options normalize to '0' while false and {capture: false} normalize to 'c=0', so a listener added one way cannot be removed the other way even though EventTarget treats both as capture: false.

I also moved the test into the existing ReactDOMFragmentRefs-test.js suite (dropping the separate test file) and reduced it to the case that still reproduces.