[JS IR] Fix referencing Kotin variables in inline JS code

Fixed by outlining JS code that uses Kotlin variables making usages of
these locals explicit and preventing bugs due to one-sided variable renaming.

This prevents using Kotlin variables as lvalue in JS code.

js/js.translator/testData/box/jsCode/label.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1285
 package foo