Scripting: Implement conditional conversion for REPL result values

to support value types erased from runtime classes. See example
in added tests for motivation.
#KT-45065 fixed
also refactor launcher repl test and result type rendering

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -309,7 +309,6 @@ class GenerationState private constructor(
 
         // and the rest is an output from the codegen
         var resultFieldName: String? = null
-        var resultTypeString: String? = null
         var resultType: KotlinType? = null
     }