tests: fix output message formatting for crypto benchmarks

tests: fix output message formatting for crypto benchmarks

The output was changed from g_print to g_test_message in

  commit 24441f912e67233d9c52ce6b459ed75de2484525
  Author: Marc-André Lureau <marcandre.lureau@redhat.com>
  Date:   Fri Aug 28 15:07:30 2020 +0400

    tests: do not print benchmark output to stdout

    As this makes the TAP output invalid. Use g_test_message().

The functions do not result in equivalent output. The g_print
statements were putting all the information on a single line
for ease of interpretation. The change to g_test_message split
the output across many lines making it painful to read.

The opportunity is used to tweak the information printed to be
more consistent across tests.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>