[CLEANUP] Remove ignored file from GIT index

The AcceptanceTester.php file is removed from GIT, as it is
listed in the .gitignore file.

Resolves: #79905
Releases: 7.6
Change-Id: I45f6d0b400a4da3a3c72587a087c40d13f5ad508
Reviewed-on: https://review.typo3.org/51758


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Thomas Hohn <thomas@hohn.dk>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Josef Glatz <josef.glatz@typo3.org>
Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>