Add functionality to window.history.go test page.

ios/testing/data/http_server_files/history_go.html

Index: ios/testing/data/http_server_files/history_go.html
diff --git a/ios/testing/data/http_server_files/history_go.html b/ios/testing/data/http_server_files/history_go.html
index 050a07dd150d0ae8e1b7daf41ecc67b7f558c1ea..25ff5b1be99989a82c89ab75ae830ba62573a0f8 100644
--- a/ios/testing/data/http_server_files/history_go.html
+++ b/ios/testing/data/http_server_files/history_go.html
@@ -27,10 +27,16 @@ found in the LICENSE file. -->
     onclick="goNoParameter()" /><br>
 <input type="button" value="go-zero" id="go-zero"
     onclick="goZero()" /><br>
+<input type="button" value="go-back" id="go-back"
+    onclick="goBack()" /><br>
+<input type="button" value="go-forward" id="go-forward"
+    onclick="goForward()" /><br>
 <input type="button" value="go-2" id="go-2"
     onclick="go2()" /><br>
 <input type="button" value="go-back-2" id="go-back-2"
     onclick="goBack2()" /><br>
+<input type="button" value="push-state-with-hash" id="push-state-with-hash"
+    onclick="pushStateWithHash()" /><br>
 
 </body>
 </html>