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

ios/web/shell/test/web_shell_navigation_egtest.mm

Index: ios/web/shell/test/web_shell_navigation_egtest.mm
diff --git a/ios/web/shell/test/web_shell_navigation_egtest.mm b/ios/web/shell/test/web_shell_navigation_egtest.mm
index 26fad4390cdf49ab6b56446d157b26ee165b0144..e3a58281a5b9764af9cfc3d648af87073c3298d2 100644
--- a/ios/web/shell/test/web_shell_navigation_egtest.mm
+++ b/ios/web/shell/test/web_shell_navigation_egtest.mm
@@ -139,11 +139,4 @@
       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