3006 VERIFY[S,U,P] and ASSERT[S,U,P] frequently check if first argument is zero

@@ -527,11 +527,11 @@
         /*
          * Print out the freelist entries in both encoded and decoded form.
          */
         alloc = 0;
         for (offset = 0; offset < smo->smo_objsize; offset += sizeof (entry)) {
-                VERIFY3U(0, ==, dmu_read(os, smo->smo_object, offset,
+                VERIFY0(dmu_read(os, smo->smo_object, offset,
                     sizeof (entry), &entry, DMU_READ_PREFETCH));
                 if (SM_DEBUG_DECODE(entry)) {
                         (void) printf("\t    [%6llu] %s: txg %llu, pass %llu\n",
                             (u_longlong_t)(offset / sizeof (entry)),
                             ddata[SM_DEBUG_ACTION_DECODE(entry)],

@@ -1186,11 +1186,11 @@
         dmu_buf_t *db;
 
         if (dump_opt['d'] < 3)
                 return;
 
-        VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
+        VERIFY0(dmu_bonus_hold(os, obj, FTAG, &db));
         bt = db->db_data;
         zdb_nicenum(bt->bt_bytes, bytes);
         (void) printf("\n    %s: %llu datasets, %s\n",
             name, (unsigned long long)(bt->bt_end - bt->bt_begin), bytes);
         dmu_buf_rele(db, FTAG);

@@ -2271,11 +2271,11 @@
             count_block_cb, &zcb, NULL);
         (void) bpobj_iterate_nofree(&spa->spa_dsl_pool->dp_free_bpobj,
             count_block_cb, &zcb, NULL);
         if (spa_feature_is_active(spa,
             &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
-                VERIFY3U(0, ==, bptree_iterate(spa->spa_meta_objset,
+                VERIFY0(bptree_iterate(spa->spa_meta_objset,
                     spa->spa_dsl_pool->dp_bptree_obj, B_FALSE, count_block_cb,
                     &zcb, NULL));
         }
 
         if (dump_opt['c'] > 1)