Make wxFileDialog::Set/SetPath() behave consistently.

wxFileDialog::GetPath() didn't return the value set by a previous call to
SetPath() in wxMSW version. Fix this and also implement SetPath() and
SetDirectory() methods in the generic versions in the same way as
SetFilename().

Closes #3672.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62722 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/filedlg.h

@@ -29,7 +29,6 @@ public:
                  const wxSize& sz = wxDefaultSize,
                  const wxString& name = wxFileDialogNameStr);
 
-    virtual void SetPath(const wxString& path);
     virtual void GetPaths(wxArrayString& paths) const;
     virtual void GetFilenames(wxArrayString& files) const;
 #ifndef __WXWINCE__