Remove misguided attempts to infer load time from incomplete round-trip data.
It turns out, those requests are from the `beforeunload` event, where a user
has left the page before it loads. Attempting to infer the `load` event from
that was clearly nonsense. Sorry, everyone.

This reverts commit cff5e9396225a3fdd594b1e7d35991c398a7ac21.
Fix failing test.