compiler: new debugging output methods/functions

Add new hooks for dumping named objects, package bindings,
and top level Gogo package list.

Change-Id: Ib162799db64fb93e61fa3156ad3ed0489ddf7c0a
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/190877
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2 files changed