[Android][Test] Remove redundant teardown in ShareButtonControllerTest

This CL removes the redundant teardown in ShareButtonControllerTest,
as the ChromeTabbedActivity is ensured to be destroyed in
ChromeTabbedActivityTestRule.

Bug: 1083138
Change-Id: Ic33e5b1d08804525d737bab44fe5fdbd4573a470
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2245625Reviewed-by: Gayane Petrosyan <gayane@chromium.org>
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779808}

chrome/android/javatests/src/org/chromium/chrome/browser/share/ShareButtonControllerTest.java

@@ -19,7 +19,6 @@ import android.view.View;
 
 import androidx.test.filters.MediumTest;
 
-import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -35,7 +34,6 @@ import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.chrome.browser.flags.ChromeSwitches;
 import org.chromium.chrome.test.ChromeJUnit4ClassRunner;
 import org.chromium.chrome.test.ChromeTabbedActivityTestRule;
-import org.chromium.chrome.test.util.ApplicationTestUtils;
 import org.chromium.chrome.test.util.ViewUtils;
 import org.chromium.chrome.test.util.browser.Features.EnableFeatures;
 import org.chromium.chrome.test.util.browser.signin.AccountManagerTestRule;
@@ -78,11 +76,6 @@ public final class ShareButtonControllerTest {
         mButtonExpected = deviceWidth > minimumWidthDp;
     }
 
-    @After
-    public void tearDown() throws Exception {
-        ApplicationTestUtils.finishActivity(mActivityTestRule.getActivity());
-    }
-
     @Test
     @MediumTest
     public void testShareButtonInToolbarIsDisabledOnStartNTP() {