Set global proxy internal field count based on the global object template.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 9e3c0372ce2e34c091dcda0510015f217c09b823..c374e8368670bff4bc883c279ccac4f1eedfc6f8 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -8504,6 +8504,8 @@ class JSGlobalProxy : public JSObject {
 
   inline bool IsDetachedFrom(JSGlobalObject* global) const;
 
+  static int SizeWithInternalFields(int internal_field_count);
+
   // Dispatched behavior.
   DECLARE_PRINTER(JSGlobalProxy)
   DECLARE_VERIFIER(JSGlobalProxy)
@@ -8512,8 +8514,6 @@ class JSGlobalProxy : public JSObject {
   static const int kNativeContextOffset = JSObject::kHeaderSize;
   static const int kHashOffset = kNativeContextOffset + kPointerSize;
   static const int kSize = kHashOffset + kPointerSize;
-  static const int kSizeWithInternalFields =
-      kSize + v8::Context::kProxyInternalFieldCount * kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSGlobalProxy);