j2k: flatten test cases and testData directory structure

Move j2k/test/tests -> j2k/tests, j2k/test/testData -> j2k/testData

j2k/testData/fileOrElement/newClassExpression/fullQualifiedName.java

@@ -0,0 +1,10 @@
+//file
+package test;
+
+import java.util.List;
+
+class User {
+  void main() {
+    List list = new java.util.ArrayList();
+  }
+}