FIR: unify common special names scattered around the code base

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt

@@ -34,6 +34,7 @@ import org.jetbrains.kotlin.ir.types.impl.makeTypeProjection
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.name.SpecialNames
 import java.io.StringWriter
 
 fun ir2string(ir: IrElement?): String = ir?.render() ?: ""
@@ -424,7 +425,7 @@ fun IrFunction.createDispatchReceiverParameter(origin: IrDeclarationOrigin? = nu
         startOffset, endOffset,
         origin ?: parentAsClass.origin,
         IrValueParameterSymbolImpl(),
-        Name.special("<this>"),
+        SpecialNames.THIS,
         -1,
         parentAsClass.defaultType,
         null,

compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/builders/declarations/declarationBuilders.kt

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.types.Variance
 
 @PublishedApi
@@ -156,7 +157,7 @@ internal fun IrFactory.buildConstructor(builder: IrFunctionBuilder): IrConstruct
     return createConstructor(
         startOffset, endOffset, origin,
         IrConstructorSymbolImpl(),
-        Name.special("<init>"),
+        SpecialNames.INIT,
         visibility, returnType,
         isInline = isInline, isExternal = isExternal, isPrimary = isPrimary, isExpect = isExpect,
         containerSource = containerSource
@@ -222,8 +223,6 @@ inline fun IrClass.addConstructor(builder: IrFunctionBuilder.() -> Unit = {}): I
         constructor.parent = this@addConstructor
     }
 
-private val RECEIVER_PARAMETER_NAME = Name.special("<this>")
-
 fun <D> buildReceiverParameter(
     parent: D,
     origin: IrDeclarationOrigin,
@@ -235,7 +234,7 @@ fun <D> buildReceiverParameter(
     parent.factory.createValueParameter(
         startOffset, endOffset, origin,
         IrValueParameterSymbolImpl(),
-        RECEIVER_PARAMETER_NAME, -1, type, null, isCrossinline = false, isNoinline = false,
+        SpecialNames.THIS, -1, type, null, isCrossinline = false, isNoinline = false,
         isHidden = false, isAssignable = false
     ).also {
         it.parent = parent