net/http/httputil: don't call WriteHeader after Hijack
CL 637939 changed ReverseProxy to report errors encountered when
copying data on an hijacked connection. This is generally not useful,
and when using the default error handler results in WriteHeader
being called on a hijacked connection.
While this is harmless with standard net/http ResponseWriter
implementations, it can confuse middleware layers.
Fixes #72954
Change-Id: I21f3d3d515e114dc5c298d7dbc3796c505d3c82f
Reviewed-on: https://go-review.googlesource.com/c/go/+/659255 Reviewed-by: Jonathan Amsterdam <jba@google.com>
Auto-Submit: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>