FIR: introduce flexible types pretty rendering for no arguments case

#KT-52020 Fixed

analysis/analysis-api/testData/components/callResolver/resolveCall/javaPropertyNestedGetter.txt

@@ -9,8 +9,8 @@ KtSuccessCallInfo:
       signature = KtVariableLikeSignature:
         name = sub
         receiverType = null
-        returnType = ft<JavaSubClass, JavaSubClass?>
-        symbol = val sub: ft<JavaSubClass, JavaSubClass?>
+        returnType = JavaSubClass!
+        symbol = val sub: JavaSubClass!
         callableIdIfNonLocal = /JavaClass.sub
     simpleAccess = Read:
 

analysis/analysis-api/testData/components/callResolver/resolveCall/samConstructorCall.txt

@@ -6,25 +6,25 @@ KtSuccessCallInfo:
       extensionReceiver = null
       signature = KtFunctionLikeSignature:
         receiverType = null
-        returnType = java.util.Comparator<ft<kotlin.Int, kotlin.Int?>>
+        returnType = java.util.Comparator<kotlin.Int!>
         symbol = java/util/Comparator(function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>): java.util.Comparator<T>
         valueParameters = [
           KtVariableLikeSignature:
             name = function
             receiverType = null
-            returnType = kotlin.Function2<ft<kotlin.Int, kotlin.Int?>, ft<kotlin.Int, kotlin.Int?>, kotlin.Int>
+            returnType = kotlin.Function2<kotlin.Int!, kotlin.Int!, kotlin.Int>
             symbol = function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>
             callableIdIfNonLocal = null
         ]
         callableIdIfNonLocal = java/util/Comparator
     typeArgumentsMapping = {
-      T -> (ft<kotlin.Int, kotlin.Int?>)
+      T -> (kotlin.Int!)
     }
     argumentMapping = {
       {x: Int, y: Int -> 1} -> (KtVariableLikeSignature:
         name = function
         receiverType = null
-        returnType = kotlin.Function2<ft<kotlin.Int, kotlin.Int?>, ft<kotlin.Int, kotlin.Int?>, kotlin.Int>
+        returnType = kotlin.Function2<kotlin.Int!, kotlin.Int!, kotlin.Int>
         symbol = function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>
         callableIdIfNonLocal = null)
     }