A bug in CheckpointHook causes false negatives

[yyyayo]

I think the globals in self.state.globals.get('globals', None) should be sym_vars. This can make CheckpointHook discard some sym_vars and give false negatives. Could you have a check if there are similar problems?

class CheckpointHook(DefaultHook):
    def run(self, **kwargs):
        assert 'arg_num' in kwargs['kwargs']
        arg_num = kwargs['kwargs']['arg_num']
        if self.state.globals.get('globals', None) is None:
            self.state.globals['sym_vars'] = []
        if arg_num == 0:
            sym_var = claripy.BVS('ret', self.state.arch.bits)
            self.state.globals['sym_vars'].append(sym_var)
            return sym_var

[jkrshnmenon]

This looks certainly like a typo. Great catch! Could you create a PR ?