Add predefined constant for $Self

Author: maxim092001

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt

@@ -63,6 +63,8 @@ class Fir2IrClassifierStorage(
 
     private val localStorage = Fir2IrLocalStorage()
 
+    private val SELF_TYPE_IDENTIFIER = Name.identifier("\$Self")
+
     private fun FirTypeRef.toIrType(typeContext: ConversionTypeContext = ConversionTypeContext.DEFAULT): IrType =
         with(typeConverter) { toIrType(typeContext) }
 
@@ -381,7 +383,7 @@ class Fir2IrClassifierStorage(
         require(index >= 0)
         val origin = typeParameter.computeIrOrigin()
         val irTypeParameter = with(typeParameter) {
-            val replacedSelfName = if (name == SELF_TYPE) Name.identifier("\$Self") else name
+            val replacedSelfName = if (name == SELF_TYPE) SELF_TYPE_IDENTIFIER else name
             convertWithOffsets { startOffset, endOffset ->
                 irFactory.createTypeParameter(
                     startOffset, endOffset, origin, IrTypeParameterSymbolImpl(),