go/types: update test case to exercise mutually recursive interfaces
go/types: update test case to exercise mutually recursive interfaces

Due to a typo, this test case was not actually exercising the bug
described in golang/go#33656. Update it to do so. Interestingly, the
comparison is now valid (as it should be) -- I suspect #33656 is
actually fixed.

Fixes #33656

Change-Id: If50a917f6477d8eb4f82f5a2a96bf5d9123ff0d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/241263
Run-TryBot: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

golang/go,golang/go,nawawi/go,nawawi/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,CAFxX/go,cloudflare/go,nawawi/go,golang/go,nawawi/go,CAFxX/go,CAFxX/go,CAFxX/go,cloudflare/go,cloudflare/go,cloudflare/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,golang/go,nawawi/go,golang/go,nawawi/go,golang/go,golang/go