Revert "We no longer need a promise around listen [obviates IMMUTANT-217]"

Looks like we still need listen to be syncrhonous - reverting. I'll try and
think of a better way to do it.

This reverts commit 297dde6cac3232615e1c389ded6ca7c03e7d7f51.
Wait longer for listen to work, and give a better (but still shitty) error message.

Also fix the listen test to not have to wait for the promise to
timeout.
Don't use the same name for two different things.
Clarity.
Rely on polyglot's context-path normalization.
Revert "Unpend these"

Pending these again so we can get a few builds out.

This reverts commit 31a2ef6222088ccb828898e9e3e4531e0333d517.