IR: minor, remove obsolete IrBasedDeclarationDescriptor

It was introduced to reference wrapped descriptors in `ir.tree`, but
since 2f544280 it's no longer necessary

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBasedDeclarationDescriptor.kt

@@ -1,10 +0,0 @@
-/*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.ir.descriptors
-
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-
-interface IrBasedDeclarationDescriptor : DeclarationDescriptor

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/WrappedDescriptors.kt

@@ -30,10 +30,7 @@ import org.jetbrains.kotlin.storage.LockBasedStorageManager
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.types.*
 
-
-abstract class WrappedDeclarationDescriptor<T : IrDeclaration>(annotations: Annotations) :
-    DeclarationDescriptor, IrBasedDeclarationDescriptor {
-
+abstract class WrappedDeclarationDescriptor<T : IrDeclaration>(annotations: Annotations) : DeclarationDescriptor {
     private val annotations_ = annotations
 
     override val annotations: Annotations

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrSymbolBase.kt

@@ -35,7 +35,7 @@ abstract class IrBindableSymbolBase<out D : DeclarationDescriptor, B : IrSymbolO
     }
 
     private fun isOriginalDescriptor(descriptor: DeclarationDescriptor): Boolean =
-        descriptor is IrBasedDeclarationDescriptor ||
+        descriptor is WrappedDeclarationDescriptor<*> ||
                 descriptor is ValueParameterDescriptor && isOriginalDescriptor(descriptor.containingDeclaration) ||
                 descriptor == descriptor.original