add traceur test suite

test/fixtures/traceur/MemberVariables/ClassExpression.module.js

@@ -0,0 +1,14 @@
+// Options: --member-variables --types --type-assertions --type-assertion-module=../TypeAssertions/resources/assert.js
+
+import '../TypeAssertions/resources/assert.js';
+
+class C extends class {
+  x: number;
+} {
+  y: number;
+}
+
+var c = new C();
+
+assert.throw(() => { c.x  = 'str'}, chai.AssertionError);
+assert.throw(() => { c.y  = 'str'}, chai.AssertionError);