j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/switch/caseWithBlock.kt

@@ -0,0 +1,17 @@
+fun foo() {
+    when (a) {
+        1 -> {
+            val x = 1
+            System.out.println(x)
+        }
+
+        2 -> {
+            val x = 2
+            System.out.println(x)
+        }
+
+        3 -> {
+            System.out.println(3)
+        }
+    }
+}