Now that states have a complete set of members, the linked list of
reductions is useless: just fill directly the state's reductions
member.
* src/state.h (struct reductions): Remove member `number' and
`next'.
* src/LR0.c (first_reduction, last_reduction): Remove.
(save_reductions): Don't link the new reductions, store them in
this_state.
* src/lalr.c (set_state_table): No need to attach reductions to
states, it's already done.
* src/output.c (output_actions): No longer free the shifts, then
the reductions, then the states: free all the states and their
members.