fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/runtime.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart._runtime;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'dart:_debugger' show stackTraceMapper;
@@ skipping 105 matching lines @@
     // These settings must be configured before the application starts so that
     // user code runs with the correct configuration.
     let settings = 'ddcSettings' in globalState ? globalState.ddcSettings : {};
     $trapRuntimeErrors(
         'trapRuntimeErrors' in settings ? settings.trapRuntimeErrors : true);
     $ignoreWhitelistedErrors(
         'ignoreWhitelistedErrors' in settings ?
             settings.ignoreWhitelistedErrors : true);
 
     $ignoreAllErrors(
-        'ignoreAllErrors' in settings ?settings.ignoreAllErrors : false);
+        'ignoreAllErrors' in settings ? settings.ignoreAllErrors : false);
 
-    $failForWeakModeIsChecks(
-        'failForWeakModeIsChecks' in settings ?
-            settings.failForWeakModeIsChecks : true);
     $trackProfile(
         'trackProfile' in settings ? settings.trackProfile : false);
 
     return globalState;
   }()
 ''');
 
 final JsSymbol = JS('', 'Symbol');