Avoid calling ssl_load_sigalgs in tls1_set_sigalgs_list

Avoid calling ssl_load_sigalgs in tls1_set_sigalgs_list

- The signature algorithms are already loaded in SSL_CTX_new()

- Calling ssl_load_sigalgs() again is non-productive, and does
  not look thread safe.

- And of course avoiding the call is cheaper.

- Also fix broken loop test in ssl_cert_lookup_by_pkey()

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26671)