Fix one off error.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 1639457e7d8acc887dd511e83cb28437827d527a..cdc249152dbe91c07d13d4c16a2ca6e09201a375 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2322,6 +2322,8 @@ class JSFunctionResultCache: public FixedArray {
   static const int kCacheSizeIndex = kFingerIndex + 1;
   static const int kDummyIndex = kCacheSizeIndex + 1;
   static const int kEntriesIndex = kDummyIndex + 1;
+
+  static const int kEntrySize = 2;  // key + value
 };