8250244: Address reliance on default constructors in java.net

Reviewed-by: alanb, vtewari

src/java.base/share/classes/java/net/SecureCacheResponse.java

@@ -39,6 +39,11 @@ import java.util.Optional;
  * @since 1.5
  */
 public abstract class SecureCacheResponse extends CacheResponse {
+    /**
+     * Constructor for subclasses to call.
+     */
+    public SecureCacheResponse() {}
+
     /**
      * Returns the cipher suite in use on the original connection that
      * retrieved the network resource.