j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/labelStatement/complicatedExampleFromJavaTutorial.kt

@@ -0,0 +1,13 @@
+@test for (i in 0..max) {
+    var n = substring.length()
+    var j = i
+    var k = 0
+    while (n-- != 0) {
+        if (searchMe.charAt(j++) != substring.charAt(k++)) {
+            continue@test
+        }
+    }
+    foundIt = true
+    break@test
+}
+System.out.println(if (foundIt) "Found it" else "Didn't find it")