Override/Implement Members: Do not expand type aliases in the generated members. Retain abbreviated types during flexible type approximation

#KT-13244 Fixed

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt

@@ -191,6 +191,7 @@ interface DescriptorRendererOptions {
     var renderDefaultAnnotationArguments: Boolean
     var alwaysRenderModifiers: Boolean
     var renderConstructorKeyword: Boolean
+    var renderUnabbreviatedType: Boolean
 }
 
 object ExcludedTypeAnnotations {

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -128,6 +128,7 @@ internal class DescriptorRendererImpl(
         if (abbreviated != null) {
             // TODO nullability is lost for abbreviated type?
             val abbreviatedRendered = renderNormalizedTypeAsIs(abbreviated.abbreviation)
+            if (!renderUnabbreviatedType) return abbreviatedRendered
             val unabbreviatedRendered = renderNormalizedTypeAsIs(abbreviated.expandedType)
             return "$abbreviatedRendered /* = $unabbreviatedRendered */"
         }

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererOptionsImpl.kt

@@ -99,4 +99,6 @@ internal class DescriptorRendererOptionsImpl : DescriptorRendererOptions {
     override var alwaysRenderModifiers by property(false)
 
     override var renderConstructorKeyword by property(true)
+
+    override var renderUnabbreviatedType: Boolean by property(true)
 }