8231202: Suppress warnings on non-serializable non-transient instance fields in serializable classes

Reviewed-by: rriggs, chegar

src/java.base/share/classes/java/time/chrono/ChronoPeriodImpl.java

@@ -109,6 +109,7 @@ final class ChronoPeriodImpl
     /**
      * The chronology.
      */
+    @SuppressWarnings("serial") // Not statically typed as Serializable
     private final Chronology chrono;
     /**
      * The number of years.