[K2 JS] Unmute and link to issue some JS K2 tests

js/js.translator/testData/box/export/vararg.kt

@@ -1,9 +1,8 @@
-// IGNORE_BACKEND: JS
-// IGNORE_BACKEND_K2: JS_IR, JS_IR_ES6
 // EXPECTED_REACHABLE_NODES: 1270
 // SKIP_MINIFICATION
 // RUN_PLAIN_BOX_FUNCTION
 // INFER_MAIN_MODULE
+// WITH_STDLIB
 
 // MODULE: vararg
 // FILE: lib.kt

js/js.translator/testData/box/expression/when/exhaustiveCheckException.kt

@@ -1,4 +1,5 @@
 // IGNORE_BACKEND_K2: JS_IR, JS_IR_ES6
+// ISSUE: KT-64652
 // EXPECTED_REACHABLE_NODES: 1323
 fun <T> checkThrown(x: T, block: (T) -> Any?): Unit? {
     return try {
@@ -93,4 +94,4 @@ fun box(): String {
     } ?: return "fail8"
 
     return "OK"
-}
+}