Convert ItemDragListenerTest to JUnit4, and add it to APCT.

package com.android.documentsui;

import static org.junit.Assert.assertFalse;

import static org.junit.Assert.assertNull;

import static org.junit.Assert.assertSame;

import static org.junit.Assert.assertTrue;

import android.content.ClipData;

import android.support.test.filters.SmallTest;

import android.support.test.runner.AndroidJUnit4;

import android.view.DragEvent;

import android.view.View;

import com.android.documentsui.testing.TestTimer;

import com.android.documentsui.testing.TestViews;

import junit.framework.TestCase;

import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.util.Timer;

import java.util.TimerTask;

public class ItemDragListenerTest extends TestCase {

@RunWith(AndroidJUnit4.class)

@SmallTest

public class ItemDragListenerTest {

    private static final long DELAY_AFTER_HOVERING = ItemDragListener.SPRING_TIMEOUT + 1;

    private TestDragListener mListener;

    @Override

    @Before

    public void setUp() {

        mTestView = TestViews.createTestView();