cmd/compile/internal/types2: match go/types error for invalid instantiations

cmd/compile/internal/types2: match go/types error for invalid instantiations

Also: add a missing test.

For #54511.

Change-Id: Ie9828c6ba5186feb5a79db0d58beb2cda2beae56
Reviewed-on: https://go-review.googlesource.com/c/go/+/426478
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>