godoc/analysis: log one error per error package.
godoc/analysis: log one error per error package.

Previously type errors were reported via the web interface but
not logged, but this led to confusion as to why SSA
construction and/or pointer analysis were not attempted.

LGTM=gri
R=gri, bradfitz
CC=golang-codereviews
https://golang.org/cl/136660043

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