FIR: introduce flexible types pretty rendering for no arguments case

#KT-52020 Fixed

compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/InheritedSimple.fir.txt

@@ -2,7 +2,7 @@ public abstract interface InheritedSimple : R|kotlin/Any| {
     public abstract interface Sub : R|test/InheritedSimple.Super| {
     }
     public abstract interface Super : R|kotlin/Any| {
-        public abstract fun foo(r: R|ft<java/lang/Runnable, java/lang/Runnable?>|): R|kotlin/Unit|
+        public abstract fun foo(r: R|java/lang/Runnable!|): R|kotlin/Unit|
 
     }
 }