Avoid manipulation of composer.json when using `runTests.sh`

[Starkmann]

Summary

When I'm using the runTest.sh locally, the composer.json will be adjusted when composer update min or max is called due to the requirement of typo3-minimal.
This can lead to accidentally committing the composer.json with the requirement of TYPO3 minimal.

Steps to reproduce the problem

1. run ./Build/Scripts/runTests.sh -s composerUpdateMax
2. check composer.json it is changed

I already did a fix for this in another extension:

undkonsorten/taskqueue@56d9a42