j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/methodCallExpression/vararg2.kt

@@ -0,0 +1,9 @@
+import javaApi.WithVarargConstructor
+
+class X {
+    fun foo() {
+        val o1 = WithVarargConstructor(1, *array<Any>("a"))
+        val o2 = WithVarargConstructor(2, array<Any>("a"), array<Any>("b"))
+        val o3 = WithVarargConstructor(2, "a")
+    }
+}