go.tools/go/types: added test case for channel make
go.tools/go/types: added test case for channel make

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://codereview.appspot.com/95910044

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