New J2K: add plain text copy-paste conversion test for new J2K

nj2k/testData/copyPastePlainText/PostProcessing.expected.kt

@@ -0,0 +1,15 @@
+package to
+
+import java.io.File
+import java.util.ArrayList
+
+
+class JavaClass {
+    internal fun foo(file: File?, target: List<String?>?) {
+        val list = ArrayList<String?>()
+        if (file != null) {
+            list.add(file.name)
+        }
+        target?.addAll(list)
+    }
+}