Handle AlreadyClosedException when bumping primary term

If the shard is already closed while bumping the primary term, this can result in an
AlreadyClosedException to be thrown. As we use asyncBlockOperations, the exception
will be thrown on a thread from the generic thread pool and end up in the uncaught
exception handler, failing our tests.

Relates to #32442

Author: ywelsch

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -2229,7 +2229,13 @@ private <E extends Exception> void bumpPrimaryTerm(long newPrimaryTerm, final Ch
                     onBlocked.run();
                 }
             },
-            e -> failShard("exception during primary term transition", e));
+            e -> {
+                try {
+                    failShard("exception during primary term transition", e);
+                } catch (AlreadyClosedException ace) {
+                    // ignore, shard is already closed
+                }
+            });
         pendingPrimaryTerm = newPrimaryTerm;
         termUpdated.countDown();
     }