Remove root target preparer from ART run-tests configuration template.

This is no longer needed since ART run-tests use paths under
`/data/local/tmp/` on device that do not require root permissions.

Test: atest --test-mapping art:postsubmit
Bug: 147814778
Bug: 147812905
Change-Id: I0f31b5d35c0777571f6f50ad9d55735845d890e8
diff --git a/test/AndroidTestTemplate.xml b/test/AndroidTestTemplate.xml
index 642d1cc..cad7ace 100644
--- a/test/AndroidTestTemplate.xml
+++ b/test/AndroidTestTemplate.xml
@@ -15,8 +15,6 @@
 -->
 <!-- Note: This test config for {MODULE} is generated from a template. -->
 <configuration description="Test module config for {MODULE}">
-    <!-- Root access is needed to push the test JAR file to the device. -->
-    <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer" />
     <target_preparer class="com.android.tradefed.targetprep.PushFilePreparer">
         <option name="cleanup" value="true" />
         <!-- TODO: Use option `push-file` instead of deprecated option