go.tools/go/types: set correct Method recv type in NewMethodSet
go.tools/go/types: set correct Method recv type in NewMethodSet

R=adonovan
CC=golang-dev
https://golang.org/cl/11602043

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