Before tools there was no way to directly import a package in another
module, and so missing packages were always marked as "all" due to being
dependencies of a package in a main module.
Tools break that assumption, and so to report errors in tool packages
correctly we need to mark packages as being in "all" even if they do not
exist.
Fixes #70582
Change-Id: I3273e0ec7910894565206de77986f5c249a5658c
Reviewed-on: https://go-review.googlesource.com/c/go/+/634155
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Sam Thanawalla <samthanawalla@google.com> Reviewed-by: Michael Matloob <matloob@golang.org>