The binary export format embeds type definitions inline as necessary,
so there's no need to add them to exportlist. Also, constants are
embedded directly by value, so they can be omitted too.

Change-Id: Id1879eb97c298a5a52f615cf9883c346c7f7bd69
Reviewed-on: https://go-review.googlesource.com/36170
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>