[JS BE] Implement accessor inlining optimization (WIP)

- enable constant folding

compiler/testData/codegen/box/intrinsics/tostring.kt

@@ -1,6 +1,7 @@
 // IGNORE_BACKEND_FIR: JVM_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS
+// IGNORE_BACKEND: JS_IR
 
 fun box(): String {
     if (239.toByte().toString() != (239.toByte() as Byte?).toString()) return "byte failed"

compiler/testData/codegen/box/strings/stringBuilderAppend.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JS_IR
-// TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS
 
 class A() {