Last snapshot bits to get working precompiled hello_world on x64.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index bacbfe82f274c3c6a75c35a24193d29ad6a0dc1d..23c1f19b1574902c70f480e47cfd7e5efcfad90c 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -376,6 +376,9 @@ class RawObject {
   void SetVMHeapObject() {
     UpdateTagBit<VMHeapObjectTag>(true);
   }
+  void ClearVMHeapObject() {
+    UpdateTagBit<VMHeapObjectTag>(false);
+  }
 
   // Support for GC remembered bit.
   bool IsRemembered() const {
@@ -410,6 +413,9 @@ class RawObject {
   bool IsFunction() {
     return ((GetClassId() == kFunctionCid));
   }
+  bool IsInstructions() {
+    return ((GetClassId() == kInstructionsCid));
+  }
 
   intptr_t Size() const {
     uword tags = ptr()->tags_;