Don't set initial size as min size for top level windows in wxMSW.

Don't set initial size as min size for top level windows in wxMSW.

This was accidentally done because wxWindowBase::CreateBase() didn't recognize
the window as being top level as it was called before the window was appended
to wxTopLevelWindows list.

Fix this by doing the same thing wxGTK already did: just call
wxTopLevelWindows.Append() before CreateBase().

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63188 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775