go.tools/go/types: add self test
go.tools/go/types: add self test

R=adonovan
CC=golang-dev
https://golang.org/cl/11739043

matryer/tools,4ad/tools,maddyonline/tools,argandas/tools,jdhenke/tools,cw2018/tools,sshetty10/tools,springning/tools,magiccao/tools,cmars/tools,matryer/tools,cw2018/tools,nicot/tools,argandas/tools,springning/tools,nicot/tools,sshetty10/tools,golang/tools,nicot/tools,cw2018/tools,syreclabs/go-tools,glasser/golang-tools,maddyonline/tools,4ad/tools,sshetty10/tools,jdhenke/tools,golang/tools,matryer/tools,josharian/tools,springning/tools,maddyonline/tools,syreclabs/go-tools,maddyonline/tools,nicot/tools,glasser/golang-tools,argandas/tools,sshetty10/tools,cmars/tools,springning/tools,dmitris/tools,runcom/tools,runcom/tools,4ad/tools,dmitris/tools,josharian/tools,syreclabs/go-tools,glasser/golang-tools,syreclabs/go-tools,glasser/golang-tools,dmitris/tools,magiccao/tools,dmitris/tools,runcom/tools,golang/tools,cw2018/tools,magiccao/tools,jdhenke/tools,cmars/tools,golang/tools,syreclabs/go-tools,cmars/tools,magiccao/tools,josharian/tools,matryer/tools,syreclabs/go-tools,josharian/tools,jdhenke/tools,runcom/tools,golang/tools,argandas/tools