Don't use the size-zero array hack to access variable data in Snapshot.

runtime/vm/globals.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_GLOBALS_H_
 #define VM_GLOBALS_H_
 
 // This file contains global definitions for the VM library only. Anything that
 // is more globally useful should be added to 'vm/globals.h'.
 
@@ skipping 37 matching lines @@
 const intptr_t kOffsetOfPtr = 32;
 
 #define OFFSET_OF(type, field)                                                 \
   (reinterpret_cast<intptr_t>(&(reinterpret_cast<type*>(kOffsetOfPtr)->field)) \
       - kOffsetOfPtr)
 
 #define OFFSET_OF_RETURNED_VALUE(type, accessor)                               \
   (reinterpret_cast<intptr_t>(                                                 \
       (reinterpret_cast<type*>(kOffsetOfPtr)->accessor())) - kOffsetOfPtr)
 
+#define OPEN_ARRAY_START(type, align)                                          \
+  do {                                                                         \
+    const uword result = reinterpret_cast<uword>(this) + sizeof(*this);        \
+    ASSERT(Utils::IsAligned(result, sizeof(align)));                           \
+    return reinterpret_cast<type*>(result);                                    \
+  } while (0)
+
 
 // A type large enough to contain the value of the C++ vtable. This is needed
 // to support the handle operations.
 typedef uword cpp_vtable;
 
 
 // When using GCC we can use GCC attributes to ensure that certain
 // contants are 16 byte aligned.
 #if defined(TARGET_OS_WINDOWS)
 #define ALIGN16 __declspec(align(16))
 #else
 #define ALIGN16 __attribute__((aligned(16)))
 #endif
 
 
 // Zap value used to indicate uninitialized handle area (debug purposes).
 #if defined(ARCH_IS_32_BIT)
 static const uword kZapUninitializedWord = 0xabababab;
 #else
 static const uword kZapUninitializedWord = 0xabababababababab;
 #endif
 
 
 }  // namespace dart
 
 #endif  // VM_GLOBALS_H_