[release-branch.go1.22] go/types, types2: handle Alias types in substitution

[release-branch.go1.22] go/types, types2: handle Alias types in substitution

Fixes #65858.
For #65778. // for x/tools/cmd/gotype

Change-Id: I67d4644b28e831926fc6c233098aa1755c57162f
Reviewed-on: https://go-review.googlesource.com/c/go/+/565835
Auto-Submit: 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>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/565840
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>