Whenever we do this, Rollup needs to materialize this as an object.
This causes it to also add the Babel compatibility property which is
unnecessary bloat. However, since when we use these, we leak the object
this often also deopts any compiler optimizations.
If we really need an object we should export default an object.
Currently there is an exception for DOMTopLevelEventTypes since
listing out the imports is a PITA and it doesn't escape so it should
get properly inlined. We should probably move to a different pattern
to avoid this for consistency though.