j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/newClassExpression/newStaticInnerClass.kt

@@ -0,0 +1,11 @@
+package demo
+
+class Foo {
+    class Bar
+}
+
+class User {
+    fun main() {
+        val boo = Foo.Bar()
+    }
+}