Fix bug that could cause a string to be incorrectly tagged as an array index.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index c10c930d31958cce7cc7953f63da4119636f69c1..fe33e7ef5110a8ac6aa57e086cc0e5cbb2c603a1 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -2986,7 +2986,8 @@ StringHasher::StringHasher(int length)
   : length_(length),
     raw_running_hash_(0),
     array_index_(0),
-    is_array_index_(0 < length_ && length_ <= String::kMaxArrayIndexSize),
+    is_array_index_(0 < length_ &&
+                    length_ <= String::kMaxCachedArrayIndexLength),
     is_first_char_(true),
     is_valid_(true) { }