[Fixit] Re-enable testNewTabButtonWithManyTabs

Re-enable TabStripTest#testNewTabButtonWithManyTabs. Tested this
locally on an emulator repeating 20 times without issue.

I'll monitor the flake dashboard to see if this starts flaking and will
investigate further if any appear.

Bug: 592961
Change-Id: Ic25a995859bbba390e7fb73a62931af7ab850c0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2124981
Commit-Queue: Calder Kitagawa <ckitagawa@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754516}

chrome/android/javatests/src/org/chromium/chrome/browser/compositor/overlays/strip/TabStripTest.java

@@ -17,7 +17,6 @@ import org.junit.runner.RunWith;
 import org.chromium.base.test.util.CallbackHelper;
 import org.chromium.base.test.util.CommandLineFlags;
 import org.chromium.base.test.util.Feature;
-import org.chromium.base.test.util.FlakyTest;
 import org.chromium.base.test.util.Restriction;
 import org.chromium.chrome.browser.compositor.layouts.components.CompositorButton;
 import org.chromium.chrome.browser.flags.ChromeSwitches;
@@ -101,7 +100,6 @@ public class TabStripTest {
     @LargeTest
     @Restriction(UiRestriction.RESTRICTION_TYPE_TABLET)
     @Feature({"TabStrip"})
-    @FlakyTest(message = "crbug.com/592961")
     public void testNewTabButtonWithManyTabs() throws Exception {
         ChromeTabUtils.newTabsFromMenu(
                 InstrumentationRegistry.getInstrumentation(), mActivityTestRule.getActivity(), 3);