[KLIB] Fix top level property index. Include const properties as well.

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

@@ -1296,7 +1296,7 @@ open class IrFileSerializer(
         // Make sure that all top level properties are initialized on library's load.
         file.declarations
             .filterIsInstance<IrProperty>()
-            .filter { it.backingField?.initializer != null && !it.isConst }
+            .filter { it.backingField?.initializer != null }
             .forEach { proto.addExplicitlyExportedToCompiler(serializeIrSymbol(it.backingField!!.symbol)) }
 
         // TODO: Konan specific