add traceur test suite

test/fixtures/traceur/Classes/ClassMethodInheritance.js

@@ -0,0 +1,23 @@
+function B() {}
+B.b = function() {
+  return 'B.b';
+};
+
+class C extends B {}
+
+assert.equal(Object.getPrototypeOf(C), B);
+assert.equal(Object.getPrototypeOf(C.prototype), B.prototype);
+
+assert.equal(C.b(), 'B.b');
+
+class D extends Object {}
+
+assert.equal(Object.getPrototypeOf(D), Object);
+assert.equal(Object.getPrototypeOf(D.prototype), Object.prototype);
+assert.equal(D.keys, Object.keys);
+
+class E {}
+
+assert.equal(Object.getPrototypeOf(E), Function.prototype);
+assert.equal(Object.getPrototypeOf(E.prototype), Object.prototype);
+assert.isFalse('keys' in E);