Make static tear-off closures a class, like instance tear-off closures.

sdk/lib/_internal/compiler/implementation/js_backend/namer.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/namer.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/js_backend/namer.dart	(revision 22664)
+++ sdk/lib/_internal/compiler/implementation/js_backend/namer.dart	(working copy)
@@ -735,6 +735,11 @@
     return getMappedGlobalName("$getterPrefix${getName(element)}");
   }
 
+  String getStaticClosureName(Element element) {
+    assert(Elements.isStaticOrTopLevelFunction(element));
+    return getMappedGlobalName("${getName(element)}\$closure");
+  }
+
   String isolatePropertiesAccess(Element element) {
     return "$isolateName.$isolatePropertiesName.${getName(element)}";
   }
@@ -752,6 +757,10 @@
     return "$CURRENT_ISOLATE.${getLazyInitializerName(element)}";
   }
 
+  String isolateStaticClosureAccess(Element element) {
+    return "$CURRENT_ISOLATE.${getStaticClosureName(element)}";
+  }
+
   String operatorIsPrefix() => r'$is';
 
   String operatorAsPrefix() => r'$as';