cmd/compile/internal/ir: remove PkgFuncName assumption that LocalPkg.Path == ""
Prep refactoring for CL 393715, after which LocalPkg.Path will no
longer be the empty string. Instead of testing `pkg.Path == ""`, we
can just test `pkg == LocalPkg`.
Updates #51734.
Change-Id: I74fff7fb383e275c9f294389d30b2220aced19e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/406059 Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>