j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/methodCallExpression/vararg1.java

@@ -0,0 +1,9 @@
+//file
+import java.lang.reflect.Constructor;
+
+class X {
+    static <T> void foo(Constructor<T> constructor, Object[] args1, Object[] args2) throws Exception {
+        constructor.newInstance(args1);
+        constructor.newInstance(args1, args2);
+    }
+}