Room 2.4.0-alpha02

@ProvidedAutoMigrationSpec is a new API for declaring that an AutoMigrationSpec will be provided at runtime via RoomDatabase.Builder#addAutoMigrationSpec(). This allows for a dependency injection framework to provide such specs when they need complex dependencies. Fix an issue with auto migrations where @DatabaseViews where not being properly re-created. Fix an issue in Room's JournalMode.TRUNCATE where the InvalidationTracker callback was sometimes being invoked invalidly, too late, or not at all.