only speed test different msg sizes when tests require a message size
only speed test different msg sizes when tests require a message size

Don't perform performance tests for different buffer sizes when the
algorithm does not care about the message size.

randombit/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,webmaster128/botan,Rohde-Schwarz-Cybersecurity/botan,webmaster128/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan,webmaster128/botan,randombit/botan,webmaster128/botan,webmaster128/botan,Rohde-Schwarz-Cybersecurity/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan