[IR] Drop IrUninitializedType

#KT-66053 Fixed

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/impl/IrTypeBase.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2024 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.
  */
 
@@ -47,20 +47,6 @@ val IrType.originalKotlinType: KotlinType?
 
 data object IrStarProjectionImpl : IrStarProjection
 
-/**
- * An instance which should be used when creating an IR element whose type cannot be determined at the moment of creation.
- *
- * Example: when translating generic functions in psi2ir, we're creating an IrFunction first, then adding IrTypeParameter instances to it,
- * and only then translating the function's return type with respect to those created type parameters.
- *
- * Instead of using this special instance, we could just make IrFunction/IrConstructor constructors allow to accept no return type,
- * however this could lead to a situation where we forget to set return type sometimes. This would result in crashes at unexpected moments,
- * especially in Kotlin/JS where function return types are not present in the resulting binary files.
- */
-data object IrUninitializedType : IrType() {
-    override val annotations: List<IrConstructorCall> = emptyList()
-}
-
 internal class ReturnTypeIsNotInitializedException(function: IrFunction) : IllegalStateException(
     "Return type is not initialized for function '${function.name}'"
 )