go/types, types2: don't register interface methods in Info.Types map
Methods declared in an interface have a signature and FuncType in the
AST, but they do not express a syntactic function type expression.
Treat them like ordinary function/method declarations and do not record
them in the Info.Types map. This removes an inconsistency in the way
function types are recorded.
Follow-up on CL 640776.
For #70908.
Change-Id: I60848f209b40b008039c014fb8b7b279361487b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/640596
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com> Reviewed-by: Alan Donovan <adonovan@google.com>