go/types, types2: add test for receiver type parameters
Issue #51503 was fixed with the rewrite in CL 594740.
Add a respective test case.
Fixes #51503.
For #51343.
Change-Id: Iff9e7e3274c5ad40789e107b6f62d17e335e2428
Reviewed-on: https://go-review.googlesource.com/c/go/+/595697 Reviewed-by: Robert Griesemer <gri@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>