Allow passing multi-line strings to wxDC::DrawText(), even under MSW.

Allow passing multi-line strings to wxDC::DrawText(), even under MSW.

Native wxMSW wxDC::DrawText() implementation doesn't support multi-line
strings so use the generic wxDC::DrawLabel() code instead. Drawing multi-line
strings now works at least in wxGTK and wxMSW, to be tested for the other
platforms.

Closes #12239.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65058 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775