Test using wxString::ToCDouble() in wxAny.

Apparently the heap corruption problems in wxOSX/PPC build are due to using
wxString::ToDouble() and not anything done specifically in wxAny at all.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74019 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775