Remove EngineClosedException

All usage has been removed in #22631, which is back ported to 5.x. This means 6.x will never get it on the wire and we can remove it

Author: bleskes

core/src/main/java/org/elasticsearch/ElasticsearchException.java

@@ -869,8 +869,7 @@ enum ElasticsearchExceptionHandle {
                 org.elasticsearch.search.SearchContextException::new, 127, UNKNOWN_VERSION_ADDED),
         SEARCH_SOURCE_BUILDER_EXCEPTION(org.elasticsearch.search.builder.SearchSourceBuilderException.class,
                 org.elasticsearch.search.builder.SearchSourceBuilderException::new, 128, UNKNOWN_VERSION_ADDED),
-        ENGINE_CLOSED_EXCEPTION(org.elasticsearch.index.engine.EngineClosedException.class,
-                org.elasticsearch.index.engine.EngineClosedException::new, 129, UNKNOWN_VERSION_ADDED),
+        // 129 was EngineClosedException
         NO_SHARD_AVAILABLE_ACTION_EXCEPTION(org.elasticsearch.action.NoShardAvailableActionException.class,
                 org.elasticsearch.action.NoShardAvailableActionException::new, 130, UNKNOWN_VERSION_ADDED),
         UNAVAILABLE_SHARDS_EXCEPTION(org.elasticsearch.action.UnavailableShardsException.class,

core/src/main/java/org/elasticsearch/index/engine/EngineClosedException.java

@@ -820,7 +820,7 @@ public void testIds() {
         ids.put(126, org.elasticsearch.index.mapper.MapperParsingException.class);
         ids.put(127, org.elasticsearch.search.SearchContextException.class);
         ids.put(128, org.elasticsearch.search.builder.SearchSourceBuilderException.class);
-        ids.put(129, org.elasticsearch.index.engine.EngineClosedException.class);
+        ids.put(129, null); // was org.elasticsearch.index.engine.EngineClosedException.class
         ids.put(130, org.elasticsearch.action.NoShardAvailableActionException.class);
         ids.put(131, org.elasticsearch.action.UnavailableShardsException.class);
         ids.put(132, org.elasticsearch.index.engine.FlushFailedEngineException.class);