Fix some rewrite tests.
Fix some rewrite tests.

In the new stack, backslashes remain backslashes all the way through,
rather than getting URL encoded.

We'll also defer the OPTIONS tests to the integration tests, since in
the full stack, the chunked body may change (but as long as things work,
that's okay).

apinf/api-umbrella,NREL/api-umbrella,apinf/api-umbrella,NREL/api-umbrella,apinf/api-umbrella,NREL/api-umbrella,NREL/api-umbrella,apinf/api-umbrella,apinf/api-umbrella