AbortSignal is an EventTarget, so addEventListener() should not throw just because the event name is something other than "abort".

Right now Boa throws a TypeError here:

const ctrl = new AbortController();
ctrl.signal.addEventListener("whatever", () => {});

Current result:

TypeError: AbortSignal only supports the 'abort' event type

Expected behavior:

• no throw
• the listener is just never fired, since AbortSignal only dispatches abort

This looks like a small conformance bug in the current AbortSignal implementation. removeEventListener() already quietly ignores unknown event names, so addEventListener() throwing here is also a bit inconsistent with the rest of the API.

Relevant implementation:

• core/runtime/src/abort/mod.rs