…eply functions.

Fixes regression created in nock#2033.
Reply functions get access to the current request via the Interceptor,
which acts as the context during the function executions.
The previous change, incorrectly moved the line where the request was attached
to the Interceptor up in the flow and out of the same microtask that calls the
reply functions. Causing requests in parallel to lose the reference to the correct request.