[Test] Enable reporting errors from fronted to testdata of codegen tests

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/insideElvis.kt

@@ -5,6 +5,7 @@
 // TODO: muted automatically, investigate should it be ran for JS or not
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
+// IGNORE_FIR_DIAGNOSTICS_DIFF
 
 tailrec fun test(counter : Int) : Int? {
     if (counter < 0) return null
@@ -15,4 +16,4 @@ tailrec fun test(counter : Int) : Int? {
 
 fun box() : String =
     if (test(100000) == 777) "OK"
-    else "FAIL"
+    else "FAIL"