backing fields resolve changed

KT-462 Consider allowing initializing properties via property names when it is safe
KT-598 Allow to use backing fields after this expression

compiler/testData/diagnostics/tests/backingField/WriteNonexistentDeclaredInHigher.jet

@@ -2,6 +2,6 @@ val y = 1
 
 class A() {
     {
-        <!UNRESOLVED_REFERENCE!>$y<!> = 1
+        <!INACCESSIBLE_BACKING_FIELD!>$y<!> = 1
     }
-}
+}