Add Object.same(_,_) to access built-in equality even for classes that may override ==.

Had to add a new metaclass for Object since it now has its own static method so we
can't just use Class as its metaclass. (We don't want *every* class to have a same(_,_)
static method.)

test/core/class/name.wren

@@ -5,5 +5,9 @@ IO.print(Foo.type.name) // expect: Foo metaclass
 
 // Make sure the built-in classes have proper names too.
 IO.print(Object.name) // expect: Object
-IO.print(Class.name) // expect: Class
 IO.print(Bool.name) // expect: Bool
+IO.print(Class.name) // expect: Class
+
+// And metaclass names.
+IO.print(Object.type.name) // expect: Object metaclass
+IO.print(Bool.type.name) // expect: Bool metaclass

test/core/class/type.wren

@@ -3,7 +3,7 @@ class Foo {}
 // A class is a class.
 IO.print(Foo is Class) // expect: true
 
-// It's metatype is also a class.
+// Its metatype is also a class.
 IO.print(Foo.type is Class) // expect: true
 
 // The metatype's metatype is Class.