tests: db: don't need to manually clear the test working directory

(integrated from komodo (trunk) change 81322 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13401 b87d16e7-d29f-4ee1-b5ec-817d645d335f
tests: db: split Python and PHP db corruption tests into separate classes

(integrated from komodo (trunk) change 81323 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13402 b87d16e7-d29f-4ee1-b5ec-817d645d335f