[heap] ObjectStats: Fix off-by-one in histogram

src/heap/object-stats.h

Index: src/heap/object-stats.h
diff --git a/src/heap/object-stats.h b/src/heap/object-stats.h
index 345c6bd140ccd12d15de6e34b3e383c6a91e00e4..4e0aec7edeac9ed9d693f702f1e0bebc745881e3 100644
--- a/src/heap/object-stats.h
+++ b/src/heap/object-stats.h
@@ -94,7 +94,7 @@ class ObjectStats {
   static const int kLastBucketShift = 19;  // >512k
   static const int kFirstBucket = 1 << kFirstBucketShift;
   static const int kLastBucket = 1 << kLastBucketShift;
-  static const int kNumberOfBuckets = kLastBucketShift - kFirstBucketShift;
+  static const int kNumberOfBuckets = kLastBucketShift - kFirstBucketShift + 1;
 
   int HistogramIndexFromSize(size_t size) {
     if (size == 0) return 0;