[TASK] Acceptance tests: Don't restart browser

To speed up acceptance tests a bit the browser is no
longer restarted between tests.

Change-Id: I03132905eed1dd6a4ccca137e0e8047b01aa6ca9
Resolves: #82652
Releases: master, 8.7
Reviewed-on: https://review.typo3.org/54262


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>