The change in DescriptorSerializer is needed so that serialized protos
of enum entry classes which are resolved in sources
(LazyClassDescriptor) and are deserialized from binaries
(EnumEntrySyntheticClassDescriptor) are the same. There are tests on
incremental compilation in JS that check that the serialized proto is
exactly the same after rebuild and after an incremental build.
#KT-22048 Fixed