Remove unused variable in test

There's basically no good reasons for these variables to exist.

ropetest/refactor/patchedasttest.py

@@ -105,7 +105,6 @@ def test_integer_literals_and_sorted_children(self):
         source = "a = 10\n"
         ast_frag = patchedast.get_patched_ast(source, True)
         checker = _ResultChecker(self, ast_frag)
-        # start = source.index('10')
         checker.check_children("Num", ["10"])
 
     def test_ellipsis(self):
@@ -127,32 +126,27 @@ def test_assign_node(self):
         source = "a = 10\n"
         ast_frag = patchedast.get_patched_ast(source, True)
         checker = _ResultChecker(self, ast_frag)
-        start = source.index("a")
         checker.check_region("Assign", 0, len(source) - 1)
         checker.check_children("Assign", ["Name", " ", "=", " ", "Num"])
-        self.assertTrue(start is not None)
 
     @testutils.only_for_versions_higher("3.6")
     def test_ann_assign_node_without_target(self):
         source = "a: List[int]\n"
         ast_frag = patchedast.get_patched_ast(source, True)
         checker = _ResultChecker(self, ast_frag)
-        start = source.index("a")
         checker.check_region("AnnAssign", 0, len(source) - 1)
         checker.check_children("AnnAssign", ["Name", "", ":", " ", "Subscript"])
-        self.assertTrue(start is not None)
 
     @testutils.only_for_versions_higher("3.6")
     def test_ann_assign_node_with_target(self):
         source = "a: int = 10\n"
         ast_frag = patchedast.get_patched_ast(source, True)
         checker = _ResultChecker(self, ast_frag)
-        start = source.index("a")
         checker.check_region("AnnAssign", 0, len(source) - 1)
         checker.check_children(
             "AnnAssign", ["Name", "", ":", " ", "Name", " ", "=", " ", "Num"]
         )
-        self.assertTrue(start is not None)
+
     def test_add_node(self):
         source = "1 + 2\n"
         ast_frag = patchedast.get_patched_ast(source, True)