Clean up the encoder/decoder/loader stores before providers

Clean up the encoder/decoder/loader stores before providers

We already had the evp method store being cleaned up before the provider
store was. This prevents issues where the method clean up functions cause
providers to clean up, which then needs access to the provider store. We
extend the same thinking to the encoder/decoder/loader stores.

Fixes #15727

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15741)