[dom] Make addEventListener throw for service worker optimization (#155)

To optimize the service worker execution behavior, this change makes
addEventListener throw when it is called after the very first
evaluation of the service worker script.
You can view, comment on, or merge this pull request online at:

  https://github.com/whatwg/dom/pull/155

-- Commit Summary --

  * Make addEventListener throw for service worker optimization

-- File Changes --

    M dom.bs (9)

-- Patch Links --

https://github.com/whatwg/dom/pull/155.patch
https://github.com/whatwg/dom/pull/155.diff

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/dom/pull/155