[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/inline/jsCodeVarDeclared.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JS_IR
-// IGNORE_BACKEND: JS_IR_ES6
 // EXPECTED_REACHABLE_NODES: 1283
 package foo