Fix tokenizer: Form feeds and multiline docstrings didn't work together

test/test_diff_parser.py

@@ -1016,20 +1016,20 @@ def test_special_no_newline_ending(differ):
 
 def test_random_character_insertion(differ):
     code1 = dedent('''\
-            def create(self):
-                1
-                if self.path is not None:
-                    return
-                # 3
-                # 4
+        def create(self):
+            1
+            if self.path is not None:
+                return
+            # 3
+            # 4
         ''')
     code2 = dedent('''\
-            def create(self):
-                1
-                if 2:
-             x       return
-                # 3
-                # 4
+        def create(self):
+            1
+            if 2:
+         x       return
+            # 3
+            # 4
         ''')
     differ.initialize(code1)
     differ.parse(code2, copies=1, parsers=3, expect_error_leaves=True)