j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/list/ForEach.kt

@@ -0,0 +1,15 @@
+// ERROR: Unresolved reference: LinkedList
+import java.util.*
+
+public class ForEach {
+    public fun test() {
+        val xs = ArrayList<Any>()
+        val ys = LinkedList<Any>()
+        for (x in xs) {
+            ys.add(x)
+        }
+        for (y in ys) {
+            xs.add(y)
+        }
+    }
+}