Delete Hashable, pull up its members to Any

Extensions on nullable types remain in Library.kt for now, but will be moved to
stdlib later
Fix function receiver type in GenerateOperationsMap

It was wrong for fake overrides of equals and hashCode. Also operations map was
regenerated after removal of Hashable and moving its members to Any
Don't produce trailing spaces in GenerateOperationsMap
Create fake overrides for deserialized enum class object

Now that Any has members, we need to make sure fake overrides are properly
generated in every class descriptor we create automatically or manually.

This fixes DescriptorSerializationTestGenerated
Minor, move method closer to its usage
Handle fake overrides of members of Any in BuiltInsReferenceResolver
JS backend: fixed an equals behavior after it became a member of jet.Any.
Add toString() to Any, fix all tests