Do not rewrite the VM isolate's symbol table during AOT snapshots.

runtime/vm/snapshot.cc

Index: runtime/vm/snapshot.cc
diff --git a/runtime/vm/snapshot.cc b/runtime/vm/snapshot.cc
index 6e46e3e432ada11dfabad89172ecb730c9ddc4b2..d81c3aa82f95cbab66462d146f0df70b95e31865 100644
--- a/runtime/vm/snapshot.cc
+++ b/runtime/vm/snapshot.cc
@@ -1437,39 +1437,6 @@ bool SnapshotWriter::HandleVMIsolateObject(RawObject* rawobj) {
 #undef VM_OBJECT_WRITE
 
 
-// An object visitor which will iterate over all the script objects in the heap
-// and either count them or collect them into an array. This is used during
-// full snapshot generation of the VM isolate to write out all script
-// objects and their accompanying token streams.
-class ScriptVisitor : public ObjectVisitor {
- public:
-  explicit ScriptVisitor(Thread* thread)
-      : objHandle_(Object::Handle(thread->zone())), count_(0), scripts_(NULL) {}
-
-  ScriptVisitor(Thread* thread, const Array* scripts)
-      : objHandle_(Object::Handle(thread->zone())),
-        count_(0),
-        scripts_(scripts) {}
-
-  void VisitObject(RawObject* obj) {
-    if (obj->IsScript()) {
-      if (scripts_ != NULL) {
-        objHandle_ = obj;
-        scripts_->SetAt(count_, objHandle_);
-      }
-      count_ += 1;
-    }
-  }
-
-  intptr_t count() const { return count_; }
-
- private:
-  Object& objHandle_;
-  intptr_t count_;
-  const Array* scripts_;
-};
-
-
 ForwardList::ForwardList(Thread* thread, intptr_t first_object_id)
     : thread_(thread),
       first_object_id_(first_object_id),