core_get_libctx: use assert() instead of ossl_assert()
core_get_libctx: use assert() instead of ossl_assert()

Using ossl_assert makes the build fail with --strict-warnings
because the ossl_assert is declared with warn_unused_result.

Reviewed-by: Matt Caswell <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14571)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl