8301627: System.exit and Runtime.exit debug logging

Reviewed-by: alanb, chegar

src/java.base/share/classes/java/lang/Runtime.java

@@ -156,6 +156,11 @@ public class Runtime {
      * <p> The {@link System#exit(int) System.exit} method is the
      * conventional and convenient means of invoking this method.
      *
+     * @implNote
+     * If the {@linkplain System#getLogger(String) system logger} for {@code java.lang.Runtime}
+     * is enabled with logging level {@link System.Logger.Level#DEBUG Level.DEBUG} the stack trace
+     * of the call to {@code Runtime.exit()} is logged.
+     *
      * @param  status
      *         Termination status.  By convention, a nonzero status code
      *         indicates abnormal termination.