[tests] refactor vae tests (#9808)
* add: autoencoderkl tests
* autoencodertiny.
* fix
* asymmetric autoencoder.
* more
* integration tests for stable audio decoder.
* consistency decoder vae tests
* remove grad check from consistency decoder.
* cog
* bye test_models_vae.py
* fix
* fix
* remove allegro
* fixes
* fixes
* fixes
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Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
