[JS IR BE] Unmute tests after adding stdlib

js/js.translator/testData/box/multideclaration/multiValForRange.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1236
 package foo
 
@@ -41,4 +40,4 @@ fun box(): String {
     if (s != "n") return "s != 'n', it: " + s
 
     return "OK"
-}
+}