Fix reflection serializer failed for IDictionary.

Author: yfakariya

src/MsgPack/Serialization/MessagePackSerializer.cs

@@ -610,12 +610,9 @@ internal static MessagePackSerializer<T> CreateReflectionInternal<T>( Serializat
 			switch ( traits.CollectionType )
 			{
 				case CollectionKind.Array:
-				{
-					return ReflectionSerializerHelper.CreateArraySerializer<T>( context, concreteType, traits, ( schema ?? PolymorphismSchema.Default ) );
-				}
 				case CollectionKind.Map:
 				{
-					return ReflectionSerializerHelper.CreateMapSerializer<T>( context, concreteType, traits, ( schema ?? PolymorphismSchema.Default ) );
+					return ReflectionSerializerHelper.CreateCollectionSerializer<T>( context, concreteType, traits, ( schema ?? PolymorphismSchema.Default ) );
 				}
 				default:
 				{

src/MsgPack/Serialization/ReflectionSerializers/ReflectionSerializerHelper.cs

@@ -52,7 +52,7 @@ public static MessagePackSerializer<T> CreateReflectionEnumMessagePackSerializer
 #endif
 		}
 
-		public static MessagePackSerializer<T> CreateArraySerializer<T>(
+		public static MessagePackSerializer<T> CreateCollectionSerializer<T>(
 			SerializationContext context,
 			Type targetType,
 			CollectionTraits traits,
@@ -126,18 +126,6 @@ genericArgumentOfKeyValuePair[ 1 ]
 			}
 		}
 
-		public static MessagePackSerializer<T> CreateMapSerializer<T>(
-			SerializationContext context,
-			Type targetType,
-			CollectionTraits traits,
-			PolymorphismSchema itemsSchema
-		)
-		{
-			return
-			( MessagePackSerializer<T> )
-				GenericSerializer.TryCreateAbstractCollectionSerializer( context, targetType, targetType, itemsSchema, traits );
-		}
-
 		public static void GetMetadata(
 			IList<SerializingMember> members,
 			SerializationContext context,