Catch AlreadyClosedException and use other IndexShard instance (#38630)

Closes #38617

Author: martijnvg

x-pack/plugin/ccr/src/test/java/org/elasticsearch/xpack/CcrIntegTestCase.java

@@ -487,9 +487,14 @@ private Map<Integer, List<DocIdSeqNoAndTerm>> getDocIdAndSeqNos(InternalTestClus
             }
             IndexShard indexShard = cluster.getInstance(IndicesService.class, state.nodes().get(shardRouting.currentNodeId()).getName())
                 .indexServiceSafe(shardRouting.index()).getShard(shardRouting.id());
-            docs.put(shardRouting.shardId().id(), IndexShardTestCase.getDocIdAndSeqNos(indexShard).stream()
-                .map(d -> new DocIdSeqNoAndTerm(d.getId(), d.getSeqNo(), 1L))  // normalize primary term as the follower use its own term
-                .collect(Collectors.toList()));
+            try {
+                docs.put(shardRouting.shardId().id(), IndexShardTestCase.getDocIdAndSeqNos(indexShard).stream()
+                    // normalize primary term as the follower use its own term
+                    .map(d -> new DocIdSeqNoAndTerm(d.getId(), d.getSeqNo(), 1L))
+                    .collect(Collectors.toList()));
+            } catch (AlreadyClosedException e) {
+                // Ignore this exception and try getting List<DocIdSeqNoAndTerm> from other IndexShard instance.
+            }
         }
         return docs;
     }