Avoid wxGraphicsContext offsetting on HiDPI displays

For a typical scale factor of 2, there won't be any odd-width lines,
and for any factor greater than 1.0, it won't be doing what was intended,
so just don't do it. See #17375

src/osx/core/dcmemory.cpp

@@ -87,7 +87,7 @@ void wxMemoryDCImpl::DoSelect( const wxBitmap& bitmap )
             CGContextSetStrokeColorSpace( bmCtx, genericColorSpace );
             SetGraphicsContext( wxGraphicsContext::CreateFromNative( bmCtx ) );
             if (m_graphicContext)
-                m_graphicContext->EnableOffset(true);
+                m_graphicContext->EnableOffset(m_contentScaleFactor <= 1);
         }
         m_ok = (m_graphicContext != NULL) ;
     }