j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/switch/emptySwitch.java

@@ -0,0 +1,11 @@
+//file
+public class NonDefault {
+    public static void main(String[] args) {
+
+        int value = 3;
+        String valueString = "";
+        switch (value) {
+        }
+        System.out.println(valueString);
+    }
+}