Title:

Add a new 3-node variant we can start adding the upstreamed versions of tests to

Description:

This covers adding a new variant that we can start adding tests to. It should use the client AMI created in PERF-5330 and run on m6g.2xlarge hardware, which we found was less noisy than r6g in PM-3547.

Context:

We'll be able to add the upstreamed versions of the test to this variant as well as other new tests.