cmd/go: run tests that require package build IDs
cmd/go: run tests that require package build IDs

These tests used to be disabled in the gofrontend since the go tool
didn't support build IDs for the gofrontend. It does now, so enable
the tests again.

Change-Id: Ie5b7a2fc8983247b616c725eb30d8f8d72f492f4
Reviewed-on: https://go-review.googlesource.com/111098
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/gofrontend,golang/gofrontend,golang/gofrontend,golang/gofrontend