Fix #12416 where copy_tag failed to inline in the RTS.
RTS: Fix failed inlining of copy_tag.
On windows using gcc-10 gcc refused to inline copy_tag into evacuate.
To fix this we no set the always_inline attribute for copy and copy_tag
to force inlining.
An earlier commit also tried to avoid evacuate_large inlining. But
didn't quite succeed. So I also marked evacuate_large as noinline.