cmd/compile/internal/types2: handle recursive type parameter constraints

Check type constraints after the respective type parameter list
has been associated with a parameterized type so that recursive
type parameter constraints "see" a parameterized type.

Fixes #45550.
Fixes #47796.

Change-Id: Iac74610ca017a78013820624230c857395506aff
Reviewed-on: https://go-review.googlesource.com/c/go/+/348090


Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>