Please update the documentation at: https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/running-codeql-code-scanning-in-a-container

The execution of a code scan where there is a build for a compiled languge can work with a build which occurs in a separate container.

This is possible running a 2-container Pod in Kubernetes using the following specification for a pod:

spec:
shareProcessNamespace: true

I can provide evidence but this is a fairly straightforward use case to implement and validate.