Allow TestEZ-CLI to accept run-in-roblox as a runner

[benbrimeyer]

In order to allow users of TestEZ-CLI to use Luau without roblox-cli. We could generically allow TestEZ-CLI to accept any runner and wait for someone to build a run-in-roblox executable compatible with TestEZ-CLI, or bring it into the library at wholesale like lemur and roblox-cli.

Breakdown on usage of run-in-roblox today: https://devforum.community/t/automated-testing-on-roblox/272