DRY reducecheck code

uncompyle6/parsers/reducecheck/ifstmts_jump.py

@@ -4,6 +4,10 @@ from uncompyle6.scanners.tok import Token
 
 
 def ifstmts_jump(self, lhs, n, rule, ast, tokens, first, last):
+
+    if len(rule[1]) <= 1 or not ast:
+        return False
+
     come_froms = ast[-1]
     # Make sure all of the "come froms" offset at the
     # end of the "if" come from somewhere inside the "if".