Simplify the orientation-sensor IDL test (#12106)

diff --git a/orientation-sensor/idlharness.https.html b/orientation-sensor/idlharness.https.html
deleted file mode 100644
index c87d99f..0000000
--- a/orientation-sensor/idlharness.https.html
+++ /dev/null
@@ -1,38 +0,0 @@
-<!DOCTYPE html>
-<meta charset="utf-8">
-<title>Orientation Sensor IDL tests</title>
-<link rel="author" title="Intel" href="http://www.intel.com">
-<link rel="help" href="https://w3c.github.io/orientation-sensor/">
-<link rel="help" href="https://w3c.github.io/sensors/">
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resources/WebIDLParser.js"></script>
-<script src="/resources/idlharness.js"></script>
-<script>
-"use strict";
-
-function doTest([dom, generic_sensor, orientation_sensor]) {
-  const idl_array = new IdlArray();
-  idl_array.add_untested_idls(dom);
-  idl_array.add_untested_idls('interface EventHandler {};');
-  idl_array.add_idls(generic_sensor, { only: ['Sensor', 'SensorOptions'] });
-  idl_array.add_idls(orientation_sensor);
-  idl_array.add_objects({
-    AbsoluteOrientationSensor: ['new AbsoluteOrientationSensor();'],
-    RelativeOrientationSensor: ['new RelativeOrientationSensor();']
-  });
-  idl_array.test();
-}
-
-function fetchText(url) {
-  return fetch(url).then((response) => response.text());
-}
-
-promise_test(() => {
-  return Promise.all([
-    "/interfaces/dom.idl",
-    "/interfaces/sensors.idl",
-    "/interfaces/orientation-sensor.idl",
-  ].map(fetchText)).then(doTest);
-}, "Test IDL implementation of Orientation Sensor");
-</script>
diff --git a/orientation-sensor/idlharness.https.window.js b/orientation-sensor/idlharness.https.window.js
new file mode 100644
index 0000000..39217fc
--- /dev/null
+++ b/orientation-sensor/idlharness.https.window.js
@@ -0,0 +1,19 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+// https://w3c.github.io/orientation-sensor/">
+
+'use strict';
+
+idl_test(
+  ['orientation-sensor'],
+  ['generic-sensor', 'dom'],
+  idl_array => {
+    idl_array.add_objects({
+      AbsoluteOrientationSensor: ['new AbsoluteOrientationSensor();'],
+      RelativeOrientationSensor: ['new RelativeOrientationSensor();']
+    });
+    idl_array.prevent_multiple_testing('OrientationSensor');
+  },
+  'Test IDL implementation of Orientation Sensor'
+);