http2: add tests to verify the type of peer stream resets

Make sure that both the server and client can see typed errors when
the peer's body is interrupted by a stream reset. grpc will need this.

Turns out things were okay, but the behavior wasn't locked in. Now it is.

Change-Id: I449a52e368efe9a3d44c59cc9a4fc15365bc4f12
Reviewed-on: https://go-review.googlesource.com/18502
Reviewed-by: Andrew Gerrand <adg@golang.org>
2 files changed