Revert "Generate tear-off closures dynamically."

dart/sdk/lib/_internal/lib/isolate_helper.dart

Index: dart/sdk/lib/_internal/lib/isolate_helper.dart
diff --git a/dart/sdk/lib/_internal/lib/isolate_helper.dart b/dart/sdk/lib/_internal/lib/isolate_helper.dart
index 283169cb2107312fdea5d089a20bc4bf9bfc96ff..5c88c49aaf6868deb63a46823cf06b258afbcadb 100644
--- a/dart/sdk/lib/_internal/lib/isolate_helper.dart
+++ b/dart/sdk/lib/_internal/lib/isolate_helper.dart
@@ -8,7 +8,6 @@ import 'dart:async';
 import 'dart:collection' show Queue, HashMap;
 import 'dart:isolate';
 import 'dart:_js_helper' show
-    Closure,
     Null,
     Primitives,
     convertDartClosureToJS;
@@ -564,7 +563,7 @@ class IsolateNatives {
   }
 
   static _getJSFunctionFromName(String functionName) {
-    return JS("", "init.globalFunctions[#]()", functionName);
+    return JS("", "init.globalFunctions[#]", functionName);
   }
 
   /**
@@ -573,7 +572,7 @@ class IsolateNatives {
    * but you should probably not count on this.
    */
   static String _getJSFunctionName(Function f) {
-    return (f is Closure) ? JS("String|Null", r'#.$name', f) : null;
+    return JS("String|Null", r"(#['$name'] || #)", f, null);
   }
 
   /** Create a new JavaScript object instance given its constructor. */