Improve helpers/cli/FixHOME

What does this MR do?

FixHOME was previously relying on an external dependency that recently deprecated some of its parts. That forced us to make some changes as in 452ac0a2 which, unfortunately, created a regression.

This commit was started with an intention to add some tests to helpers/cli/fixHOME so that we will not repeat the same regression in the past. However, during a short discussion we had about the problem, we've decided that the code we're relying on is so simple that we could just bring it to runner's codebase directly, shaping the FixHOME behavior in the way we expected it to work and dropping the dependency usage.

Why was this MR needed?

What's the best way to test this MR?

What are the relevant issue numbers?