The ifError alias for error in tapjs appears to no longer exist.

This one was rather strange. These tests fail even if parallel test
running is disabled (tap --jobs=1). Explicitly listening to a different
port on each test case solved the issue. I then tried waiting for the
next event cycle using a setTimeout(..., 0) on t.end and this actually
worked. I suspect then that the server doesn't really "close" until the
event loop turns once more - very interesting.

After the previous changes there were a few lingering asserts that
didn't match the names in the newest version of tap. These were
relatively trivial to fix, although interestingly the meaning of the
'includes' synonym changed at some point from "match" to "has"; these
tests were written at the time "includes" meant "match".