message: Fix alignment flag for emit_small_memory_copy
  Do not unconditionally pass the "aligned" MemFlag when calling
  emit_small_memory_copy.  Instead, allow the back end to rely on
  the alignment info passed separately to this routine.
diff: @@ -614,7 +614,7 @@ fn transmute_value<'tcx>(
  dst_align,
  src_align,
  true,
  - MemFlags::trusted(),
  + flags,
  );
  }
  CValueInner::ByRef(_, Some(_)) => todo!(),
  