rework-testing: Don't use the previous environment to clean the database before a test run, but instantiate the database connection directly.
rework-testing: Don't use the previous environment to clean the database before a test run, but instantiate the database connection directly.

Part of #8169.


git-svn-id: aefd11945137af0f31499d1cc9b63b54ed7ebb20@8156 af82e41b-90c4-0310-8c96-b1721e28e2e2

jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,netjunki/trac-Pygit2,jun66j5/trac-ja,jun66j5/trac-ja,walty8/trac,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,walty8/trac