Revert "SOLR-9132: Fix request-counting logic in ConnectionReuseTest"

The logic for request-counting is different in master and 6.x, due to the
difference in HttpClient implementations.

This reverts commit a35057fff2.

solr/core/src/test/org/apache/solr/client/solrj/ConnectionReuseTest.java

@@ -149,7 +149,7 @@ public class ConnectionReuseTest extends SolrCloudTestCase {
       // we try and make sure the connection we get has handled all of the requests in this test
       if (client instanceof ConcurrentUpdateSolrClient) {
         // we can't fully control queue polling breaking up requests - allow a bit of leeway
-        int exp = queueBreaks + 3;
+        int exp = cnt1 + queueBreaks + 2;
         assertTrue(
             "We expected all communication via streaming client to use one connection! expected=" + exp + " got="
                 + metrics.getRequestCount(),