Avoid using constructor.name on ff & safari

sdk/lib/_internal/js_runtime/lib/native_helper.dart

Index: sdk/lib/_internal/js_runtime/lib/native_helper.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/native_helper.dart b/sdk/lib/_internal/js_runtime/lib/native_helper.dart
index c6aad9430c4302c697a8244b7b667d39de0029fd..d3ef5f200042fea09e353fee897013e39e92a27e 100644
--- a/sdk/lib/_internal/js_runtime/lib/native_helper.dart
+++ b/sdk/lib/_internal/js_runtime/lib/native_helper.dart
@@ -497,30 +497,6 @@ function() {
  */
 const _constructorNameFallback = const JS_CONST(r'''
 function getTagFallback(o) {
-  var constructor = o.constructor;
-  if (typeof constructor == "function") {
-    var name = constructor.name;
-    // If the name is a non-empty string, we use that as the type name of this
-    // object.  There are various cases where that does not work, so we have to
-    // detect them and fall through to the toString() based implementation.
-
-    if (typeof name == "string" &&
-
-        // Sometimes the string is empty.  This test also catches minified
-        // shadow dom polyfil wrapper for Window on Firefox where the faked
-        // constructor name does not 'stick'.  The shortest real DOM object
-        // names have three characters (e.g. URL, CSS).
-        name.length > 2 &&
-
-        // On Firefox we often get "Object" as the constructor name, even for
-        // more specialized DOM objects.
-        name !== "Object" &&
-
-        // This can happen in Opera.
-        name !== "Function.prototype") {
-      return name;
-    }
-  }
   var s = Object.prototype.toString.call(o);
   return s.substring(8, s.length - 1);
 }''');