Track which entries in the ObjectPool are native entries, and reset them when loading a precompiled…

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
diff --git a/runtime/vm/assembler_x64.h b/runtime/vm/assembler_x64.h
index 5cb3c177044d977de426fa2bc85c2682cdefb770..a6d64db0dc3f2c5be230533751d6b06868353567 100644
--- a/runtime/vm/assembler_x64.h
+++ b/runtime/vm/assembler_x64.h
@@ -763,6 +763,9 @@ class Assembler : public ValueObject {
   void LoadExternalLabel(Register dst,
                          const ExternalLabel* label,
                          Patchability patchable);
+  void LoadNativeEntry(Register dst,
+                       const ExternalLabel* label,
+                       Patchability patchable);
   void LoadFunctionFromCalleePool(Register dst,
                                   const Function& function,
                                   Register new_pp);