Not to my knowledge. I'd just do something simple by changing your CloudFormation (or Terraform or whatever) templates, deploying the new config, and then running another load test. Could also just spin multiple different versions of the Lambda up, but at some point you need to start getting creative to actually generate enough traffic and running multiple load tests at the same time becomes a pain.

When it comes to load testing tools I like Vegeta[1], personally. (Though I've also used some much more complicated proprietary tools when testing at great scale.)

1: https://github.com/tsenart/vegeta

In Serverless Framework you can specify memory per function so it stands to reason making multiple copies at different memory levels would be pretty easy to test, even concurrently.