Use correct return type for constructor call when creating EnumDescriptor

Previous one was converted using obsolete API, which caused unbound symbols to appear.

#KT-41321 Fixed

(cherry picked from commit c881347)

Author: sandwwraith

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt

@@ -77,18 +77,18 @@ class SerializerForEnumsGenerator(
         +irReturn(getValueByOrdinal)
     }
 
+    override val serialDescImplClass: ClassDescriptor = serializerDescriptor
+        .getClassFromInternalSerializationPackage(SerialEntityNames.SERIAL_DESCRIPTOR_FOR_ENUM)
+
     override fun IrBlockBodyBuilder.instantiateNewDescriptor(
         serialDescImplClass: ClassDescriptor,
         correctThis: IrExpression
     ): IrExpression {
-        val serialDescForEnums = serializerDescriptor
-            .getClassFromInternalSerializationPackage(SerialEntityNames.SERIAL_DESCRIPTOR_FOR_ENUM)
-        val ctor = compilerContext.referenceConstructors(serialDescForEnums.fqNameSafe).single { it.owner.isPrimary }
+        val ctor = compilerContext.referenceConstructors(serialDescImplClass.fqNameSafe).single { it.owner.isPrimary }
         return irInvoke(
             null, ctor,
             irString(serialName),
-            irInt(serializableDescriptor.enumEntries().size),
-            typeHint = ctor.descriptor.returnType.toIrType()
+            irInt(serializableDescriptor.enumEntries().size)
         )
     }
 

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt

@@ -52,11 +52,11 @@ open class SerializerIrGenerator(val irClass: IrClass, final override val compil
     protected val irAnySerialDescProperty = anySerialDescProperty?.let { compilerContext.symbolTable.referenceProperty(it) }
 
 
-    override fun generateSerialDesc() {
-        val desc: PropertyDescriptor = generatedSerialDescPropertyDescriptor ?: return
-        val serialDescImplClass = serializerDescriptor
+    protected open val serialDescImplClass: ClassDescriptor = serializerDescriptor
             .getClassFromInternalSerializationPackage(SERIAL_DESCRIPTOR_CLASS_IMPL)
 
+    override fun generateSerialDesc() {
+        val desc: PropertyDescriptor = generatedSerialDescPropertyDescriptor ?: return
         val addFuncS = serialDescImplClass.referenceMethod(CallingConventions.addElement)
 
         val thisAsReceiverParameter = irClass.thisReceiver!!