New J2K: add multi-file conversion tests from old j2k

nj2k/testData/multiFile/ProtectedVisibility/InheritorOtherPackage1.kt

@@ -0,0 +1,6 @@
+package test
+
+open class BaseOtherPackage protected constructor() {
+    protected fun foo() {}
+    protected var i = 1
+}