IR: remove IrTerminalExpressionBase, Ir{Terminal,}DeclarationReferenceBase

Implement no-op acceptChildren/transformChildren in the base class
IrExpressionBase instead. This doesn't change behavior because all other
implementations of acceptChildren/transformChildren are not affected.

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/inline/FunctionInlining.kt

@@ -511,7 +511,7 @@ class FunctionInlining(
     private class IrGetValueWithoutLocation(
         override val symbol: IrValueSymbol,
         override val origin: IrStatementOrigin? = null
-    ) : IrTerminalDeclarationReferenceBase<IrValueSymbol>(), IrGetValue {
+    ) : IrExpressionBase(), IrGetValue {
         override val startOffset: Int get() = UNDEFINED_OFFSET
         override val endOffset: Int get() = UNDEFINED_OFFSET
 
@@ -537,4 +537,4 @@ class InlinerExpressionLocationHint(val inlineAtSymbol: IrSymbol) : IrStatementO
 
     private val functionNameOrDefaultToString: String
         get() = (inlineAtSymbol as? IrFunction)?.name?.asString() ?: inlineAtSymbol.toString()
-}
+}