Allow 4 more fast properties for objects.

Review URL: http://codereview.chromium.org/6016003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6084 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.h

@@ -1734,7 +1734,7 @@ class JSObject: public HeapObject {
   static const uint32_t kMaxGap = 1024;
   static const int kMaxFastElementsLength = 5000;
   static const int kInitialMaxFastElementArray = 100000;
-  static const int kMaxFastProperties = 8;
+  static const int kMaxFastProperties = 12;
   static const int kMaxInstanceSize = 255 * kPointerSize;
   // When extending the backing storage for property values, we increase
   // its size by more than the 1 entry necessary, so sequentially adding fields