ci: Criterion benchmark handlers

[dougch]

Resolved issues:

part of #3130

Description of changes:

Changes to the Criterion benchmarks allow a criterion to call s2nc or s2nd.

Call-outs:

• This is one of four PRs.
• These changes are only enabled when S2N_USECRITERION is set.
• s2nc and s2nd must be in the path.

Testing:

How is this change tested (unit tests, fuzz tests, etc.)? ci

Is this a refactor change? not exactly

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.