Fix _wrapDartFunction to call the JS set method directly. At one point this code was previously sur…

pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart

Index: pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart
diff --git a/pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart b/pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart
index 4e2d6fd9c6ce1f56ea61d7bad5fd9b97bf71297d..1582f0d679219ac1d2e5573d6ce4c8ea33d52ffa 100644
--- a/pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart
+++ b/pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart
@@ -470,7 +470,8 @@ dynamic _wrapDartFunction(f) {
       '  let args = Array.prototype.map.call(arguments, #);'
       '  return #(#(...args));'
       '}', _convertToDart, _convertToJS, f);
-  _dartProxies[wrapper] = f;
+  JS('', '#.set(#, #)', _dartProxies, wrapper, f);
+
   return wrapper;
 }