Prefer VERIFY0(n) over VERIFY3U(n, ==, 0)

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/
Closes #17591

cmd/zdb/zdb.c

@@ -1456,7 +1456,7 @@ get_obsolete_refcount(vdev_t *vd)
 		}
 	} else {
 		ASSERT3P(vd->vdev_obsolete_sm, ==, NULL);
-		ASSERT3U(obsolete_sm_object, ==, 0);
+		ASSERT0(obsolete_sm_object);
 	}
 	for (unsigned c = 0; c < vd->vdev_children; c++) {
 		refcount += get_obsolete_refcount(vd->vdev_child[c]);

cmd/ztest.c

@@ -4006,7 +4006,7 @@ raidz_scratch_verify(void)
 		 * requested by user, but scratch object was not created.
 		 */
 		case RRSS_SCRATCH_NOT_IN_USE:
-			ASSERT3U(offset, ==, 0);
+			ASSERT0(offset);
 			break;
 
 		/*