Migrate flags from bit_field2 to bit_field3

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 0d3a206ee7671dbc5ee8e3c912e7bbd5ea73e1cf..92a854a56f0b7bd165931bc5bb531076d3140434 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -3989,8 +3989,10 @@ class Map: public HeapObject {
   static const int kHasFastElements = 2;
   static const int kStringWrapperSafeForDefaultValueOf = 3;
   static const int kAttachedToSharedFunctionInfo = 4;
-  static const int kIsShared = 5;
-  static const int kHasExternalArrayElements = 6;
+  static const int kHasExternalArrayElements = 5;
+
+  // Bit positions for bit field 3
+  static const int kIsShared = 1;
 
   // Layout of the default cache. It holds alternating name and code objects.
   static const int kCodeCacheEntrySize = 2;