Added missing permission to test manifest file.

PermissionPolicyTest fails due to missing permission
HIDE_NON_SYSTEM_OVERLAY_WINDOWS.

Fixes: 64314283
Test: android.permission2.cts.PermissionPolicyTest#testPlatformPermissionPolicyUnaltered

Change-Id: I921544174d96917aee95035b632db8bb8ab13cff
diff --git a/tests/tests/permission2/res/raw/android_manifest.xml b/tests/tests/permission2/res/raw/android_manifest.xml
index b6b2f92..15ed98f 100644
--- a/tests/tests/permission2/res/raw/android_manifest.xml
+++ b/tests/tests/permission2/res/raw/android_manifest.xml
@@ -2143,6 +2143,15 @@
     <permission android:name="android.permission.INTERNAL_SYSTEM_WINDOW"
                 android:protectionLevel="signature" />
 
+    <!-- @SystemApi Allows an application to use
+        {@link android.view.WindowManager.LayoutsParams#PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS}
+        to hide non-system-overlay windows.
+        <p>Not for use by third-party applications.
+        @hide
+    -->
+    <permission android:name="android.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS"
+                android:protectionLevel="signature|installer" />
+
     <!-- @SystemApi Allows an application to manage (create, destroy,
          Z-order) application tokens in the window manager.
          <p>Not for use by third-party applications.