go.types, types2: factor out isUntypedNumeric predicate
No need for Unalias or under calls for this predicate.
Change-Id: Idcdcda3e153d829ee5b26ad112ccfda3f4efedde
Reviewed-on: https://go-review.googlesource.com/c/go/+/581255 Reviewed-by: Robert Griesemer <gri@google.com> Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Robert Griesemer <gri@google.com>