Tests will be in net/http in a separate CL.

Updates golang/go#23010

Change-Id: I91a6875b9a59b33a3c669e73dd6632ac523eb9f6
Reviewed-on: https://go-review.googlesource.com/86255Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>