add further tests.

Author: pdvrieze

serialization/src/commonTest/kotlin/nl/adaptivity/xml/serialization/TestCommon.kt

@@ -35,7 +35,6 @@ fun String.normalizeXml() = replace(" />", "/>")
     .replace(" ?>", "?>")
     .replace("\r\n", "\n")
     .replace(">", ">")
-    .replace(" ?>", "?>")
 
 fun JsonBuilder.defaultJsonTestConfiguration() {
     isLenient = true