net/http: revert change to generated file from CL 296152

This file is generated, so the fix needs to happen upstream.
The file can then be regenerated using 'go generate net/http'.

Updates #44143

Change-Id: I13a1e7677470ba84a06976e5bbe24f4ce1e7cfb2
Reviewed-on: https://go-review.googlesource.com/c/go/+/301069


Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>