go.tools/cmd/vet: remove duplicate test file
go.tools/cmd/vet: remove duplicate test file

In CL 145360043, I hg cp'd copylock.go to copylock_func.go instead of hg mv. Oops.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/143660043

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