IR: make IrBody and subtypes classes

compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/expressions/persistent/PersistentIrBlockBody.kt

@@ -29,10 +29,7 @@ internal class PersistentIrBlockBody(
     override val startOffset: Int,
     override val endOffset: Int,
     override var initializer: (PersistentIrBlockBody.() -> Unit)? = null
-) :
-    PersistentIrBodyBase<PersistentIrBlockBody>,
-    IrBlockBody {
-
+) : IrBlockBody(), PersistentIrBodyBase<PersistentIrBlockBody> {
     override var lastModified: Int = stageController.currentStage
     override var loweredUpTo: Int = stageController.currentStage
     override var values: Array<Carrier>? = null

compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/expressions/persistent/PersistentIrExpressionBody.kt

@@ -30,10 +30,7 @@ internal class PersistentIrExpressionBody private constructor(
     override val endOffset: Int,
     private var expressionField: IrExpression? = null,
     override var initializer: (PersistentIrExpressionBody.() -> Unit)? = null
-) :
-    PersistentIrBodyBase<PersistentIrExpressionBody>,
-    IrExpressionBody {
-
+) : IrExpressionBody(), PersistentIrBodyBase<PersistentIrExpressionBody> {
     override var lastModified: Int = stageController.currentStage
     override var loweredUpTo: Int = stageController.currentStage
     override var values: Array<Carrier>? = null