Revert "Disable BottomToolbarTest causing build bot failures."

This reverts commit 51a51ab0.

Reason for revert: Tests already restricted to phones only

Original change's description:
> Disable BottomToolbarTest causing build bot failures.
> 
> Bug: 1009145, 1009146
> TBR=twellington@chromium.org
> 
> Change-Id: I8211bcc1dcf78da8b9782f421ad962da051c7e9c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1830328
> Reviewed-by: Ender <ender@google.com>
> Commit-Queue: Ender <ender@google.com>
> Auto-Submit: Ender <ender@google.com>
> Cr-Commit-Position: refs/heads/master@{#700940}

TBR=ender@google.com

Change-Id: I383a47998ee17efdffbbf8265107a5ee6be6ccff
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1009145, 1009146
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1829773Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700947}

chrome/android/javatests/src/org/chromium/chrome/browser/toolbar/bottom/BottomToolbarTest.java

@@ -16,7 +16,6 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CommandLineFlags;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Restriction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
@@ -53,7 +52,6 @@ public class BottomToolbarTest {
     }
 
     @Test
-    @DisabledTest
     @MediumTest
     public void testBottomToolbarVisibility() {
         Assert.assertNotNull("BottomToolbarCoordinator should be constructed.",
@@ -65,7 +63,6 @@ public class BottomToolbarTest {
     }
 
     @Test
-    @DisabledTest
     @MediumTest
     public void testBottomToolbarTabSwitcherButton() throws ExecutionException {
         Assert.assertFalse("Tab switcher should not be visible.",