TEST: Index diff num docs in rolling upgrade tests (#34191)

Today we index the same number of documents (50 documents) in each round
of the rolling upgrade tests. If the actual count does not match, we can
not guess the problematic round.

Relates #27650

qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/RecoveryIT.java

@@ -148,12 +148,12 @@ public void testRecoveryWithConcurrentIndexing() throws Exception {
                 break;
             case UPGRADED:
                 updateIndexSettings(index, Settings.builder().put(INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.getKey(), (String)null));
-                asyncIndexDocs(index, 60, 50).get();
+                asyncIndexDocs(index, 60, 45).get();
                 ensureGreen(index);
                 client().performRequest(new Request("POST", index + "/_refresh"));
-                assertCount(index, "_only_nodes:" + nodes.get(0), 110);
-                assertCount(index, "_only_nodes:" + nodes.get(1), 110);
-                assertCount(index, "_only_nodes:" + nodes.get(2), 110);
+                assertCount(index, "_only_nodes:" + nodes.get(0), 105);
+                assertCount(index, "_only_nodes:" + nodes.get(1), 105);
+                assertCount(index, "_only_nodes:" + nodes.get(2), 105);
                 break;
             default:
                 throw new IllegalStateException("unknown type " + CLUSTER_TYPE);
@@ -165,7 +165,7 @@ private void assertCount(final String index, final String preference, final int
         request.addParameter("preference", preference);
         final Response response = client().performRequest(request);
         final int actualCount = Integer.parseInt(ObjectPath.createFromResponse(response).evaluate("count").toString());
-        assertThat(actualCount, equalTo(expectedCount));
+        assertThat("preference [" + preference + "]", actualCount, equalTo(expectedCount));
     }
 
 
@@ -225,17 +225,17 @@ public void testRelocationWithConcurrentIndexing() throws Exception {
                     .put(IndexMetaData.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 2)
                     .put("index.routing.allocation.include._id", (String)null)
                 );
-                asyncIndexDocs(index, 60, 50).get();
+                asyncIndexDocs(index, 60, 45).get();
                 ensureGreen(index);
                 client().performRequest(new Request("POST", index + "/_refresh"));
                 Response response = client().performRequest(new Request("GET", "_nodes"));
                 ObjectPath objectPath = ObjectPath.createFromResponse(response);
                 final Map<String, Object> nodeMap = objectPath.evaluate("nodes");
                 List<String> nodes = new ArrayList<>(nodeMap.keySet());
 
-                assertCount(index, "_only_nodes:" + nodes.get(0), 110);
-                assertCount(index, "_only_nodes:" + nodes.get(1), 110);
-                assertCount(index, "_only_nodes:" + nodes.get(2), 110);
+                assertCount(index, "_only_nodes:" + nodes.get(0), 105);
+                assertCount(index, "_only_nodes:" + nodes.get(1), 105);
+                assertCount(index, "_only_nodes:" + nodes.get(2), 105);
                 break;
             default:
                 throw new IllegalStateException("unknown type " + CLUSTER_TYPE);