CSHARP-5329: Fix RetryableWrites_testCase__insertOne-serverErrors.json_RetryableWriteError_label_is_not_added_based_on_writeConcernError_in_pre-4.4_mongos_response test (#1498)

Author: sanych-sun

src/MongoDB.Driver/Core/MongoCommandException.cs

@@ -90,7 +90,7 @@ protected MongoCommandException(SerializationInfo info, StreamingContext context
         /// <value>
         /// The error code.
         /// </value>
-        public virtual int Code
+        public int Code
         {
             get { return _result.GetValue("code", -1).ToInt32(); }
         }

src/MongoDB.Driver/Core/MongoWriteConcernException.cs

@@ -91,20 +91,6 @@ public MongoWriteConcernException(SerializationInfo info, StreamingContext conte
             AddErrorLabelsFromWriteConcernResult(this, _writeConcernResult);
         }
 
-        /// <inheritdoc/>
-        public override int Code
-        {
-            get
-            {
-                if (WriteConcernResult.Response["writeConcernError"].AsBsonDocument.TryGetValue("code", out var code))
-                {
-                    return code.AsInt32;
-                }
-
-                return base.Code;
-            }
-        }
-
         // properties
         /// <summary>
         /// Gets the mapped write concern result exception.

tests/MongoDB.Driver.Tests/UnifiedTestOperations/Matchers/UnifiedErrorMatcher.cs

@@ -183,7 +183,7 @@ private void AssertWriteConcernErrors(Exception actualException, BsonArray expec
                 clientBulkWriteException.WriteConcernErrors.Select(
                     e => new BsonDocument
                     {
-                        { "code", e.Code },
+                        { "code", ((MongoCommandException)e.MappedWriteConcernResultException).Code },
                         { "message", e.Message }
                     }));