add symexec bindings for testing
add symexec bindings for testing

f-prettyland/angr,axt/angr,chubbymaggie/simuvex,chubbymaggie/angr,iamahuman/angr,f-prettyland/angr,chubbymaggie/simuvex,chubbymaggie/angr,schieb/angr,angr/angr,iamahuman/angr,tyb0807/angr,iamahuman/angr,schieb/angr,chubbymaggie/angr,angr/angr,angr/angr,axt/angr,tyb0807/angr,angr/simuvex,schieb/angr,axt/angr,chubbymaggie/simuvex,f-prettyland/angr,tyb0807/angr,zhuyue1314/simuvex