Guard against `toString` returning null in TableDump
Guard against `toString` returning null in TableDump

Fixes #1308.
nremond/slick,nremond/slick,xavier-fernandez/slick,xavier-fernandez/slick,Radsaggi/slick,kwark/slick,nremond/slick,Asamsig/slick,AtkinsChang/slick,xavier-fernandez/slick,marko-asplund/slick,trevorsibanda/slick,AtkinsChang/slick,nafg/slick,Radsaggi/slick