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

js/js.translator/testData/box/esModules/incremental/jsModule.kt

@@ -1,4 +1,3 @@
-// IGNORE_FIR
 // SKIP_IR_INCREMENTAL_CHECKS
 // DONT_TARGET_EXACT_BACKEND: JS
 // ES_MODULES
@@ -40,4 +39,4 @@ export function fooF() {
 // FILE: bar.mjs
 export function barF() {
     return "bar";
-}
+}