net/http: regenerate http2 bundle with bundle fixes to include comments

The golang.org/x/tools/cmd/bundle tool previously had a bug where it
dropped some comments.

This regenerates it with the fixed version (https://golang.org/cl/45117).

(Upstream is still git rev 3470a06c1, from https://golang.org/cl/44331)

Updates #20548

Change-Id: Ic5d9208a0c8f7facdb7b315c6acab66ace34c0a9
Reviewed-on: https://go-review.googlesource.com/45158Reviewed-by: Hiroshi Ioka <hirochachacha@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>