lcl: introduce TCustomForm.Resize for compatibility with VCL, move window state change logic there

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42100 4005530d-fff6-0310-9dd1-cebe43e6787f
lcl: formatting

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42101 4005530d-fff6-0310-9dd1-cebe43e6787f