tests/basics/builtin_locals: Add test for using locals() in class body.

tests/basics/builtin_locals.py

@@ -2,3 +2,12 @@
 
 x = 123
 print(locals()['x'])
+
+class A:
+    y = 1
+    def f(self):
+        pass
+
+    print('x' in locals())
+    print(locals()['y'])
+    print('f' in locals())