MicrodroidTestApp is a self-instrumenting test

This is a first step for making our tests to run on device.
MicrodroidTestApp now becomes a self-instrumenting test. The test
currently does nothing at the moment though.

Bug: 203483081
Test: atest MicrodroidTestApp
Change-Id: I675f622e9d014fb1bb358d4ab537dcd5377ba2ba
diff --git a/tests/testapk/AndroidManifest.xml b/tests/testapk/AndroidManifest.xml
index 94f49dd..21abeb5 100644
--- a/tests/testapk/AndroidManifest.xml
+++ b/tests/testapk/AndroidManifest.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright (C) 2021 The Android Open Source Project
+
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
@@ -14,13 +15,10 @@
 -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="com.android.microdroid.test">
-    <application android:label="Microdroid Test">
+    <application>
         <uses-library android:name="android.system.virtualmachine" android:required="true" />
-        <activity android:name="TestActivity" android:exported="true">
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
-        </activity>
     </application>
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.android.microdroid.test"
+        android:label="Microdroid Test" />
 </manifest>