godoc: Update identifier indexing tests.
godoc: Update identifier indexing tests.

R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/48170043

lattera/go.tools,chenjianlong/go.tools,chenjianlong/go.tools,chenjianlong/go.tools,karmakaze/go.tools,lattera/go.tools,lattera/go.tools,karmakaze/go.tools,karmakaze/go.tools,karmakaze/go.tools,karmakaze/go.tools