- Move VM specific helpers to the common dart:io patch file.

runtime/bin/common_patch.dart

Index: runtime/bin/common_patch.dart
===================================================================
--- runtime/bin/common_patch.dart	(revision 42671)
+++ runtime/bin/common_patch.dart	(working copy)
@@ -6,3 +6,11 @@
   /* patch */ static Uint8List getRandomBytes(int count)
       native "Crypto_GetRandomBytes";
 }
+
+
+// Provide a closure which will allocate a Timer object to be able to hook
+// up the Timer interface in dart:isolate with the implementation here.
+_getTimerFactoryClosure() {
+  runTimerClosure = _Timer._handleTimeout;
+  return _Timer._factory;
+}