fcl-db: tests: change TestAutoCommit test to not use multiple transactions, as this results in "false negative" for SQL Connections, which does not support multiple simultaneous transactions

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@29194 3ad0048d-3df7-0310-abae-a5850022a9f2
fcl-db: tests: fix probably by accident commit in rev.29109

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@29195 3ad0048d-3df7-0310-abae-a5850022a9f2