go.tools/go/types: enable another test case
go.tools/go/types: enable another test case

Working now that circular interface types are handled correcly.

R=adonovan
CC=golang-dev
https://codereview.appspot.com/16310046

skyportsystems/go.tools,d0f/go-zh.tools,bryanxu/go-zh.tools,skyportsystems/go.tools,bryanxu/go-zh.tools,skyportsystems/go.tools,webfd/go-zh.tools,skyportsystems/go.tools,d0f/go-zh.tools,bryanxu/go-zh.tools,d0f/go-zh.tools,8limbs/gotools,d0f/go-zh.tools,webfd/go-zh.tools,bryanxu/go-zh.tools,8limbs/gotools,skyportsystems/go.tools,webfd/go-zh.tools,webfd/go-zh.tools,bryanxu/go-zh.tools,8limbs/gotools,d0f/go-zh.tools,webfd/go-zh.tools