Free one bit in Map by removing unused retaining counter.

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index ea5dec8e7179947fbb787d832922bd05288330fa..dcb8f0e5d217b9cb349757a3b20ad8562d89a8cb 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -484,7 +484,7 @@ void Map::MapPrint(std::ostream& os) {  // NOLINT
   os << "\n - constructor: " << Brief(GetConstructor());
   os << "\n - code cache: " << Brief(code_cache());
   os << "\n - dependent code: " << Brief(dependent_code());
-  os << "\n - counter: " << counter();
+  os << "\n - construction counter: " << construction_counter();
   os << "\n";
 }