[FIR] Prepare commonization of PostponedArgumentInputTypesResolver

core/compiler.common/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -232,6 +232,7 @@ interface TypeSystemContext : TypeSystemOptimizationContext {
 
     fun KotlinTypeMarker.argumentsCount(): Int
     fun KotlinTypeMarker.getArgument(index: Int): TypeArgumentMarker
+    fun KotlinTypeMarker.getArguments(): List<TypeArgumentMarker>
 
     fun SimpleTypeMarker.getArgumentOrNull(index: Int): TypeArgumentMarker? {
         if (index in 0 until argumentsCount()) return getArgument(index)

core/descriptors/src/org/jetbrains/kotlin/types/checker/ClassicTypeSystemContext.kt

@@ -161,6 +161,11 @@ interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext, TypeSy
         return this.arguments[index]
     }
 
+    override fun KotlinTypeMarker.getArguments(): List<TypeArgumentMarker> {
+        require(this is KotlinType, this::errorMessage)
+        return this.arguments
+    }
+
     override fun TypeArgumentMarker.isStarProjection(): Boolean {
         require(this is TypeProjection, this::errorMessage)
         return this.isStarProjection