Migrate ChainedTasksTest to use Batched execution.

BUG=

Change-Id: Iba9b613656bf8ff6ba4c9e5c4ebdec3854582931
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2502782Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821364}

chrome/android/javatests/src/org/chromium/chrome/browser/init/ChainedTasksTest.java

@@ -12,6 +12,7 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.task.PostTask;
 import org.chromium.base.test.BaseJUnit4ClassRunner;
+import org.chromium.base.test.util.Batch;
 import org.chromium.content_public.browser.UiThreadTaskTraits;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
 
@@ -25,6 +26,7 @@ import java.util.concurrent.TimeUnit;
  * Tests for {@link ChainedTasks}.
  */
 @RunWith(BaseJUnit4ClassRunner.class)
+@Batch(Batch.UNIT_TESTS)
 public class ChainedTasksTest {
     private static final long TIMEOUT_MS = 1000;