Update some testdata according to new inference behaviour

compiler/testData/diagnostics/tests/when/withSubjectVariable/smartCastOnValueBoundToSubjectVariable.kt

@@ -1,4 +1,5 @@
 // !LANGUAGE: +VariableDeclarationInWhenSubject
+// !WITH_NEW_INFERENCE
 
 fun foo(s1: Int, s2: Int) = s1 + s2
 
@@ -43,6 +44,6 @@ fun test5(x: Inv<out Any?>) {
 
 fun test6(x: Inv<out String?>) {
     when (val <!UNUSED_VARIABLE!>y<!> = x.data) {
-        is String -> <!DEBUG_INFO_SMARTCAST!>x.data<!>.length // should be ok
+        is String -> <!OI;DEBUG_INFO_SMARTCAST!>x.data<!><!NI;UNSAFE_CALL!>.<!>length // should be ok
     }
 }