Fix skip logic if test is skipped both on server and for some databases

If the Skip annotation is added to a test method with both server=true
and for a particular database, the test should only run if neither
applies.

Fixes the patch for bug 401069, which caused an error on the (actually
skipped) MySQL platform.

Signed-off-by: Sabine Heider <sabine.heider@sap.com>