CFGFast: fix fast jumptable resolution.
CFGFast: fix fast jumptable resolution.

This commit fixes issue #322 on GitHub.

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