Run ios-safari tests on try bots

lib/web_ui/dev/test_runner.dart

@@ -16,7 +16,6 @@ import 'package:test_core/src/executable.dart'
     as test; // ignore: implementation_imports
 import 'package:simulators/simulator_manager.dart';
 
-import 'common.dart';
 import 'environment.dart';
 import 'exceptions.dart';
 import 'integration_tests_manager.dart';
@@ -122,12 +121,6 @@ class TestCommand extends Command<bool> with ArgUtils {
     SupportedBrowsers.instance
       ..argParsers.forEach((t) => t.parseOptions(argResults));
 
-    // Mac Web Engine Try bots are failing. Investigate further.
-    // TODO: https://github.com/flutter/flutter/issues/60251
-    if(isSafariOnMacOS && isLuci) {
-      return true;
-    }
-
     // Check the flags to see what type of integration tests are requested.
     testTypesRequested = findTestType();
 

lib/web_ui/pubspec.yaml

@@ -26,7 +26,7 @@ dev_dependencies:
     git:
       url: git://github.com/flutter/web_installers.git
       path: packages/simulators/
-      ref: 9ede7e3c069180b28322bb3f0d0307c824071fb5
+      ref: 1da6bb8df222f0d124e737e8abc20d68ddb7ea43
   web_driver_installer:
     git:
       url: git://github.com/flutter/web_installers.git