Add POST support to XHR as well as .status and statusText support

sky/tests/framework/xmlhttprequest/responseType.sky

Index: sky/tests/framework/xmlhttprequest/responseType.sky
diff --git a/sky/tests/framework/xmlhttprequest/responseType.sky b/sky/tests/framework/xmlhttprequest/responseType.sky
index 5153093f5b9159503f5cdc948043e8951df21416..f220009b87804b043aebf6269dca977e7c0081d4 100644
--- a/sky/tests/framework/xmlhttprequest/responseType.sky
+++ b/sky/tests/framework/xmlhttprequest/responseType.sky
@@ -4,12 +4,11 @@
 <import src="/sky/framework/xmlhttprequest.sky" as="XMLHttpRequest" />
 <script>
 describe("xmlhttprequest.responseType", function() {
-  this.enableTimeouts(false);
-
-  it("should support arraybuffer", function() {
+  it("should support arraybuffer", function(done) {
     var xhr = new XMLHttpRequest();
+    xhr.responseType = 'arraybuffer';
     xhr.onload = function() {
-      assert.typeOf(this.response, "arraybuffer", "Response is an arraybuffer\n");
+      assert.instanceOf(xhr.response, ArrayBuffer, "Response is an ArrayBuffer\n");
       done();
     };
     xhr.open("GET", "resources/pass.txt");