files: when filtering search results, ensure results are children of the fakeroot not just path starting the same

when storing back the data field 'encrypted' it is necessary to cast the boolean to an integer to make pg happy

- giving the user a new id for each test run in order to prevent reuse of e.g. permissions data in the database
- setting the current user id because \OC\FilesView relies on \OC_User::getUser()