cmd/guru: if query file is not beneath GOPATH, treat it as a package

This allows type-based guru queries to work on arbitrary files at the
root or even outside of a GOPATH workspace (as "go run foo.go" does).

Fixes golang/go#15797

Change-Id: I2be28f7259448e6398aae84d6ae7e71d8649967a
Reviewed-on: https://go-review.googlesource.com/30451
Reviewed-by: Robert Griesemer <gri@golang.org>
1 file changed