Don't inherit metaclasses.

Also disallow super() in static methods. It won't do anything
useful (it always just delegates to Class) anyway.

test/inheritance/do_not_inherit_static_methods.wren

@@ -0,0 +1,7 @@
+class Foo {
+  static methodOnFoo { IO.print("foo") }
+}
+
+class Bar is Foo {}
+
+Bar.methodOnFoo // expect runtime error: Receiver does not implement method 'methodOnFoo'.