Revert unnecessary PKCS7_verify() performance optimization
Revert unnecessary PKCS7_verify() performance optimization

It appears that creating temporary read-only mem BIO won't increase performance significally
anymore. But it increases PKCS7_verify() complexity, so should be removed.

Reviewed-by: Paul Dale <ddec78389666b4f7c9b4d110380c848489a3e4aa@openssl.org>
Reviewed-by: Dmitry Belyavskiy <38c64d6e24766247aad56af3a6ddb0056ad36a44@gmail.com>
Reviewed-by: Tomas Mraz <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16590)

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