dcache-bulk: fix warning for premature stop of job container

Motivation:

On cancellation, it is possible to see:

08 Sep 2023 08:22:24 [pool-8-thread-19] [] Uncaught exception in thread pool-8-thread-19java.lang.RuntimeException: run container called with
container in wrong state STOP; this is a bug.
	at org.dcache.services.bulk.job.AbstractRequestContainerJob.run(AbstractRequestContainerJob.java:330)
	at org.dcache.util.FireAndForgetTask.run(FireAndForgetTask.java:28)
	at org.dcache.util.CDCExecutorServiceDecorator$WrappedRunnable.run(CDCExecutorServiceDecorator.java:130)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at
com.google.common.util.concurrent.TrustedListenableFutureTask$TrustedFutureInterruptibleTask.runInterruptibly(TrustedListenableFutureTask.java:131)
	at com.google.common.util.concurrent.InterruptibleTask.run(InterruptibleTask.java:75)
	at com.google.common.util.concurrent.TrustedListenableFutureTask.run(TrustedListenableFutureTask.java:82)
	at org.dcache.util.BoundedExecutor$Worker.run(BoundedExecutor.java:247)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

While this error would be appropriate for other states, it is possible
to encounter a run `STOP` state upon (re)calling `run()` now that listing is
multithreaded.

Modification:

Log the condition and exit.

Result:

Avoids stack traces which are not really from a bug but from a multithreaded
cancel.

Target: master
Patch: https://rb.dcache.org/r/14093/
Requires-notes: no (unreleased change in https://rb.dcache.org/r/14041/)
Ackec-by: Tigran

modules/dcache-bulk/src/main/java/org/dcache/services/bulk/job/AbstractRequestContainerJob.java

@@ -326,6 +326,11 @@ public void run() {
                     containerState = ContainerState.STOP;
                     update(COMPLETED);
                     break;
+                case STOP:
+                    LOGGER.debug("run {} was prematurely stopped; exiting", ruid);
+                    update(CANCELLED);
+                    setRunThread(null);
+                    return;
                 default:
                     throw new RuntimeException(
                           "run container called with container in wrong state " + containerState