fix: Tap Test improvements/fixes

[candrews]

• [X] Follows CONTRIBUTING rules

What does this PR do?

Supports parallelism in the tap tests by using different XDG Configuration directories and fakeserver ports for each tap test process. Also fixes a few minor problems in the tap tests.

Where should the reviewer start?

Run the tap tests.

How should this be manually tested?

npm run test:tap

Any background context you want to provide?

I'm splitting out some of the changes in https://github.com/snyk/cli/pull/3875 into separate PRs for easier review/merging.

What are the relevant tickets?

n/a

Screenshots

n/a

Additional questions

n/a

[candrews]

@PeterSchafer hopefully this small PR passes all tests and is very easy to merge :)

[thisislawatts]

Parallelism support added in: https://github.com/snyk/cli/pull/4989