This is to help with debugging, and to allow us to write tests that do not
rely on hard coded constants.
Change-Id: Ica9ed5eee3d35539fe50d76276988852e62b81ca
Reviewed-on: https://go-review.googlesource.com/c/tools/+/172401
Run-TryBot: Ian Cottrell <iancottrell@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
