Fix tests: "infix modifier required" and "operator modifier required" errors

js/js.translator/testData/expression/invoke/cases/invokeMethod.kt

@@ -1,7 +1,7 @@
 package foo
 
 class Foo(val postfix: String) {
-    public fun invoke(text: String): String {
+    operator fun invoke(text: String): String {
         return text + postfix
     }
 }