allow disabling of ArrayBuffer neutering

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index f6c4d19e66e485354f85a2dba7f90cbc76249011..d513f979226806e4be9ae6f5c69b0c64996c1e1b 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -9961,6 +9961,9 @@ class JSArrayBuffer: public JSObject {
   inline bool should_be_freed();
   inline void set_should_be_freed(bool value);
 
+  inline bool is_neuterable();
+  inline void set_is_neuterable(bool value);
+
   // [weak_next]: linked list of array buffers.
   DECL_ACCESSORS(weak_next, Object)
 
@@ -9990,6 +9993,7 @@ class JSArrayBuffer: public JSObject {
   // Bit position in a flag
   static const int kIsExternalBit = 0;
   static const int kShouldBeFreed = 1;
+  static const int kIsNeuterableBit = 2;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSArrayBuffer);
 };