Revert "Create temporary Earl Grey test that is flaky on FYI."

ios/web/shell/test/web_shell_navigation_egtest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <UIKit/UIKit.h>
 #import <WebKit/WebKit.h>
 #import <XCTest/XCTest.h>
 
 #import <EarlGrey/EarlGrey.h>
 
@@ skipping 121 matching lines @@
       performAction:grey_tap()];
   [[EarlGrey selectElementWithMatcher:web::addressFieldText(URL1.spec())]
       assertWithMatcher:grey_notNil()];
 
   [[EarlGrey selectElementWithMatcher:web::forwardButton()]
       performAction:grey_tap()];
   [[EarlGrey selectElementWithMatcher:web::addressFieldText(URL2.spec())]
       assertWithMatcher:grey_notNil()];
 }
 
-// Tests that sometimes passing and failing makes the bots red.
-// TODO(crbug.com/614729): Remove this test once it is verified that
-// infrastructure is properly working.
-- (void)testCoinFlip {
-  GREYAssertTrue(arc4random_uniform(10) < 5, @"Failed coin flip.");
-}
-
 @end