Use non-dead Device Orientation tests link

Let's hope web-platform-tests/wpt#350 gets merged at some point

index.html

@@ -267,7 +267,7 @@ <h1>The&#160;Web&#160;platform: Browser&#160;technologies</h1>
   <a class=pleaseUse href="http://html5please.com/#geolocation">⚑</a>
   <dd><a href="https://w3c.github.io/deviceorientation/spec-source-orientation.html">Device Orientation</a>
   <a class=caniuse href="http://caniuse.com/#feat=deviceorientation">ⓤ</a>
-  <a class=tests href="http://w3c-test.org/html/tests/submission/MOSQUITO/device-orientation/">ⓣ</a>
+  <a class=tests href="https://github.com/w3c/web-platform-tests/pull/350">ⓣ</a>
   <dd><a href="https://w3c.github.io/screen-orientation/">Screen Orientation</a>
   <a class=caniuse href="http://caniuse.com/#feat=screen-orientation">ⓤ</a>
   <a class=mdn href="https://developer.mozilla.org/en-US/docs/Web/API/Screen/orientation">ⓜ</a>