j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/function/varVararg.kt

@@ -0,0 +1,8 @@
+package demo
+
+class Test {
+    fun test(vararg args: Any) {
+        var args = args
+        args = array(1, 2, 3)
+    }
+}