8231262: Suppress warnings on non-serializable instance fields in security libs serializable classes

Reviewed-by: mullan, chegar

src/java.base/share/classes/java/security/GuardedObject.java

@@ -52,7 +52,9 @@ public class GuardedObject implements java.io.Serializable {
     @java.io.Serial
     private static final long serialVersionUID = -5240450096227834308L;
 
+    @SuppressWarnings("serial") // Not statically typed as Serializable
     private Object object; // the object we are guarding
+    @SuppressWarnings("serial") // Not statically typed as Serializable
     private Guard guard;   // the guard
 
     /**

src/java.base/share/classes/java/security/SecureRandom.java

@@ -1043,6 +1043,7 @@ public class SecureRandom extends java.util.Random {
     /**
      * @serial
      */
+    @SuppressWarnings("serial") // Not statically typed as Serializable
     private MessageDigest digest = null;
     /**
      * @serial