x509: fix double locking problem

This reverts commit 9aa4be691f5c73eb3c68606d824c104550c053f7 and removed the
redundant flag setting.

Fixes #19643

Fixes LOW CVE-2022-3996

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19652)
