Relax http stream.next closure assertion (#120480)

Author: mhl-b

modules/transport-netty4/src/main/java/org/elasticsearch/http/netty4/Netty4HttpRequestBodyStream.java

@@ -75,13 +75,15 @@ public void addTracingHandler(ChunkHandler chunkHandler) {
 
     @Override
     public void next() {
-        assert closing == false : "cannot request next chunk on closing stream";
         assert handler != null : "handler must be set before requesting next chunk";
         requestContext = threadContext.newStoredContext();
         channel.eventLoop().submit(() -> {
             activityTracker.startActivity();
             requested = true;
             try {
+                if (closing) {
+                    return;
+                }
                 if (buf == null) {
                     channel.read();
                 } else {

muted-tests.yml

@@ -241,9 +241,6 @@ tests:
 - class: org.elasticsearch.search.ccs.CrossClusterIT
   method: testCancel
   issue: https://github.com/elastic/elasticsearch/issues/108061
-- class: org.elasticsearch.http.netty4.Netty4IncrementalRequestHandlingIT
-  method: testOversizedChunkedEncoding
-  issue: https://github.com/elastic/elasticsearch/issues/120444
 - class: org.elasticsearch.xpack.logsdb.seqno.RetentionLeaseRestIT
   issue: https://github.com/elastic/elasticsearch/issues/120434
 - class: org.elasticsearch.entitlement.qa.EntitlementsAllowedIT