[KLIB] Improve performance a bit

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrFileDeserializer.kt

@@ -919,7 +919,9 @@ abstract class IrFileDeserializer(val logger: LoggingContext, val builtIns: IrBu
     }
 
     private fun eraseDelegatedSymbol(symbol: IrSymbol) {
-        delegatedSymbolMap.remove(symbol)
+        if (symbol is IrDelegatingSymbol<*, *, *>) {
+            delegatedSymbolMap.remove(symbol)
+        }
     }
 
     private inline fun <T : IrDeclarationParent> T.usingParent(block: T.() -> Unit): T =

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrFileSerializer.kt

@@ -1233,7 +1233,7 @@ open class IrFileSerializer(
 
             // TODO: keep order similar
             val sigIndex = protoIdSignatureMap[idSig] ?: error("Not found ID for $idSig (${it.render()})")
-            topLevelDeclarations.add(TopLevelDeclaration(sigIndex, it.descriptor.toString(), byteArray))
+            topLevelDeclarations.add(TopLevelDeclaration(sigIndex, idSig.toString(), byteArray))
             proto.addDeclarationId(sigIndex)
         }