Use fatbit for anch log, delay slots in scratch

Since these structures are in scratch, they do not have to be as small
as possible and we can use fatbit instead of multibit to improve
performance.

src/rose/rose_internal.h

@@ -447,7 +447,6 @@ struct RoseEngine {
     u32 size; // (bytes)
     u32 anchoredMatches; /* number of anchored roles generating matches */
     u32 delay_count; /* number of delayed literal ids. */
-    u32 delay_slot_size; /* size of delay slot mmbit. */
     u32 delay_base_id; /* literal id of the first delayed literal.
                         * delayed literal ids are contiguous */
     u32 anchored_count; /* number of anchored literal ids */