LCL: fix TabControl extra spacing (all around). LCL's TTabControl is inn reality a container, that has a real TTabcontrol on Top. The container itself must not behave as A tabcontrol widget (or it will get spacing dictated that it should not have)

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42557 4005530d-fff6-0310-9dd1-cebe43e6787f