Fix wxDC::DrawRectangle() when using RTL in wxMSW.

Extend the correct edge of the rectangle (always the physical right, not the
logical right) to fix off by one errors in RTL mode, affecting notably wxGrid.

See #16250.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77028 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Remove dynamic loading of GDI functions from wxMSW wxDC code.

All of these functions (AlphaBlend(), SetLayout(), SetWorldTransform(), ...)
are available in XP which is the minimally required version.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77029 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775