added info about smart casts to diagnostic tests

compiler/testData/diagnostics/tests/nullabilityAndAutoCasts/kt2146.kt

@@ -4,35 +4,35 @@ package kt2146
 fun f1(s: Int?): Int {
     return when (s) {
         null -> 3
-        else -> s
+        else -> <!DEBUG_INFO_AUTOCAST!>s<!>
     }
 }
 
 fun f2(s: Int?): Int {
     return when (s) {
         !is Int -> <!TYPE_MISMATCH!>s<!>
-        else -> s
+        else -> <!DEBUG_INFO_AUTOCAST!>s<!>
     }
 }
 
 fun f3(s: Int?): Int {
     return when (s) {
-        is Int -> s
+        is Int -> <!DEBUG_INFO_AUTOCAST!>s<!>
         else -> <!TYPE_MISMATCH!>s<!>
     }
 }
 
 fun f4(s: Int?): Int {
     return when {
-        s == 4 -> s
+        s == 4 -> <!DEBUG_INFO_AUTOCAST!>s<!>
         s == null -> <!TYPE_MISMATCH!>s<!>
-        else -> s
+        else -> <!DEBUG_INFO_AUTOCAST!>s<!>
     }
 }
 
 fun f5(s: Int?): Int {
     return when (s) {
-        s!! -> s
+        s!! -> <!DEBUG_INFO_AUTOCAST!>s<!>
         s -> <!TYPE_MISMATCH!>s<!>
         else -> 0
     }
@@ -40,7 +40,7 @@ fun f5(s: Int?): Int {
 
 fun f6(s: Int?): Int {
     return when {
-        s is Int -> s
+        s is Int -> <!DEBUG_INFO_AUTOCAST!>s<!>
         else -> <!TYPE_MISMATCH!>s<!>
     }
 }
@@ -48,6 +48,6 @@ fun f6(s: Int?): Int {
 fun f7(s: Int?): Int {
     return when {
         s !is Int -> <!TYPE_MISMATCH!>s<!>
-        else -> s
+        else -> <!DEBUG_INFO_AUTOCAST!>s<!>
     }
 }