Eliminate object table and use regular object pool for deoptimization infos.

runtime/vm/assembler_arm64.h

Index: runtime/vm/assembler_arm64.h
===================================================================
--- runtime/vm/assembler_arm64.h	(revision 45086)
+++ runtime/vm/assembler_arm64.h	(working copy)
@@ -475,8 +475,13 @@
     ASSERT(buffer_.pointer_offsets().length() == 0);  // No pointers in code.
     return buffer_.pointer_offsets();
   }
-  const GrowableObjectArray& object_pool() const { return object_pool_.data(); }
 
+  const GrowableObjectArray& object_pool_data() const {
+    return object_pool_.data();
+  }
+
+  ObjectPool& object_pool() { return object_pool_; }
+
   bool use_far_branches() const {
     return FLAG_use_far_branches || use_far_branches_;
   }