[JS] Remove non-functional IGNORE_FIR directive in js box tests

js/js.translator/testData/box/esModules/crossModuleRefPerModule/callableObjectRef.kt

@@ -1,4 +1,3 @@
-// IGNORE_FIR
 // DONT_TARGET_EXACT_BACKEND: JS
 // ES_MODULES
 // SPLIT_PER_MODULE
@@ -27,4 +26,4 @@ fun box(): String {
     if (b != "OK") return "fail: inline: $a"
 
     return "OK"
-}
+}