Always check CRYPTO_LOCK_{read,write}_lock

Always check CRYPTO_LOCK_{read,write}_lock

Some functions that lock things are void, so we just return early.

Also make ossl_namemap_empty return 0 on error.  Updated the docs, and added
some code to ossl_namemap_stored() to handle the failure, and updated the
tests to allow for failure.

Fixes: #14230
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14238)