apps/speed: allow to continue tests after any init failure handling.
previouly the exit(1) call was aborting the whole execution.
Improve error message.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10078)
