This change will provide a more useful error when you
are self importing a package. It has TODOs in place to propagate the
"import cycle not allowed" error from go list to the user.
Updates golang/go#33085
Change-Id: Ia868a7c688b0f0a7a9689cfda5ea8cea8ae1faff
Reviewed-on: https://go-review.googlesource.com/c/tools/+/209857
Run-TryBot: Rohan Challa <rohan@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>