VFGJob: fix issues in callstack_repr().
VFGJob: fix issues in callstack_repr().

axt/angr,schieb/angr,axt/angr,iamahuman/angr,tyb0807/angr,f-prettyland/angr,f-prettyland/angr,f-prettyland/angr,angr/angr,tyb0807/angr,schieb/angr,tyb0807/angr,angr/angr,chubbymaggie/angr,iamahuman/angr,axt/angr,angr/angr,chubbymaggie/angr,iamahuman/angr,chubbymaggie/angr,schieb/angr