Do not throw exception on not-found serialized class from knm

konan/library-reader/src/org/jetbrains/kotlin/serialization/konan/KonanClassDataFinder.kt

diff --git a/konan/library-reader/src/org/jetbrains/kotlin/serialization/konan/KonanClassDataFinder.kt b/konan/library-reader/src/org/jetbrains/kotlin/serialization/konan/KonanClassDataFinder.kt
index 2d5ea1a..e86679c 100644
--- a/konan/library-reader/src/org/jetbrains/kotlin/serialization/konan/KonanClassDataFinder.kt
+++ b/konan/library-reader/src/org/jetbrains/kotlin/serialization/konan/KonanClassDataFinder.kt
@@ -23,8 +23,9 @@
         val nameList = proto.classNameList
 
         val index = nameList.indexOfFirst { nameResolver.getClassId(it) == classId }
-        if (index == -1)
-            error("Could not find serialized class $classId")
+        if (index == -1) {
+            return null
+        }
 
         val foundClass = proto.getClasses(index) ?: error("Could not find data for serialized class $classId")