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

js/js.translator/testData/box/initialize/uninitializedLateinit.kt

@@ -1,4 +1,3 @@
-// IGNORE_FIR
 // IGNORE_BACKEND: JS_IR, JS_IR_ES6
 // EXPECTED_REACHABLE_NODES: 1336
 // MODULE: lib
@@ -61,4 +60,4 @@ fun box(): String {
     checkException("c") { C().useC() }
 
     return "OK"
-}
+}