Tests: started test for PageControl

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42679 4005530d-fff6-0310-9dd1-cebe43e6787f
LCL: PageControl, fixed active page should not change (same tabsheet, may be at new index) if moving pages

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42680 4005530d-fff6-0310-9dd1-cebe43e6787f