K2: Imitate K1 behavior for case of captured types with a raw supertype

See the comments in the code, but mostly the motivation is that once
it was decided to stick with such a legacy thing as raw types,
we are ok with some corner-cases hacks for them
(if there are not too many of them) and they don't break anything
when there are no raw types in the code.

^KT-56616 Fixed

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/ConeInferenceContext.kt

@@ -558,6 +558,11 @@ interface ConeInferenceContext : TypeSystemInferenceExtensionContext, ConeTypeCo
 
     override fun useRefinedBoundsForTypeVariableInFlexiblePosition(): Boolean = true
 
+    override fun KotlinTypeMarker.convertToNonRaw(): KotlinTypeMarker {
+        require(this is ConeKotlinType)
+        return this.convertToNonRawVersion()
+    }
+
     override fun createSubstitutorForSuperTypes(baseType: KotlinTypeMarker): TypeSubstitutorMarker? =
         if (baseType is ConeLookupTagBasedType) createSubstitutionForSupertype(baseType, session) else null