Move deferred self-test lock to FIPS_GLOBAL

Move deferred self-test lock to FIPS_GLOBAL

The lock for the deferred FIPS self-tests was previously a static
global variable, initialized with CRYPTO_ONCE. This is problematic
when multiple library contexts are used in a single application.

This change moves the lock into the FIPS_GLOBAL structure, making it
per-library-context. The lock is now initialized when the FIPS
provider is initialized and freed when its context is torn down.
This improves encapsulation and avoids global state.

Signed-off-by: Simo Sorce <simo@redhat.com>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/29222)