net/http: add test for proxyAuth
Change-Id: Ib4edae749ce8da433e992e08a90c9cf3d4357081
GitHub-Last-Rev:
19d87d12ab6b299b37e8907429f4dff52ab53745
GitHub-Pull-Request: golang/go#46102
Reviewed-on: https://go-review.googlesource.com/c/go/+/318690
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>