MINOR: time: remove useless variable copies in tv_update_date()

MINOR: time: remove useless variable copies in tv_update_date()

In the global_now loop, we used to set tmp_adj from adjusted, then
set update it from tmp_now, then set adjusted back to tmp_adj, and
finally set now from adjusted. This is a long and unneeded set of
moves resulting from years of code changes. Let's just set now
directly in the loop, stop using adjusted and remove tmp_adj.