remove redundant assertion messages, wxLogError has already been called

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76278 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
assertion messages don't need to be translated

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76279 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775