[JS IR BE] Fix and refactor interop tests

js/js.translator/testData/box/jsName/secondaryConstructor.kt

@@ -1,13 +1,12 @@
 // IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1288
-package foo
 
 class A(val x: String) {
     @JsName("A_int") constructor(x: Int) : this("int $x")
 }
 
 fun test() = js("""
-return JS_TESTS.foo.A_int(23).x;
+return JS_TESTS.A_int(23).x;
 """)
 
 fun box(): String {