[Misc] reuse num_tokens_across_dp of get_dp_padding to avoid unnecessary dp all reduce in set_forward_context (#18935)
Signed-off-by: Tyler Michael Smith <tysmith@redhat.com>
Co-authored-by: zhuhaoran <zhuhaoran.zhr@alibaba-inc.com>
Co-authored-by: Tyler Michael Smith <tysmith@redhat.com>