Refactor wxStatusBar creation in wxMSW to do it in standard way.

Refactor wxStatusBar creation in wxMSW to do it in standard way.

Use wxControl-provided CreateControl() and MSWCreateControl() methods to
create the status bar instead of duplicating their code in its Create().

Also translate wx styles to MSW ones in overridden MSWGetStyle() now.

In addition to making the code smaller and more clear, this fixes the
non-respect of the styles specified at status bar creation (e.g. border),
see #12655.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66227 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775