gitlab-ci.yml: Merge check-crypto-old jobs into the build-crypto-old jobs

Both, the build-crypto-old and the check-crypto-old jobs finish reasonably
fast, and the build artifacts are only used for the single corresponding
check jobs, so there is no reason for doing the check step in a separate
job here. Thus let's stop wasting artifacts space and job scheduler over-
head by simply merging the test step into the build jobs.

Message-Id: <20210311142211.1547864-5-thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>