New J2K: Split old j2k and new j2k tests

j2k/testData/fileOrElement/trait/interfaceWithFields.kt

@@ -2,6 +2,6 @@ internal interface INode {
     companion object {
         val IN = "in"
         val AT = "@"
-        val COMMA_WITH_SPACE = IN + AT
+        val COMMA_WITH_SPACE = COMMA + SPACE
     }
 }