tests: cli_user: zfs_001_neg: print the problematic lines

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13352

tests/zfs-tests/tests/functional/cli_user/misc/zfs_001_neg.ksh

@@ -55,6 +55,6 @@ TEMPFILE="$TEST_BASE_DIR/zfs_001_neg.$$.txt"
 zfs > $TEMPFILE 2>&1
 log_must grep "usage: zfs command args" "$TEMPFILE"
 
-log_must awk '{if (length($0) > 80) exit 1}' $TEMPFILE
+log_must awk 'length($0) > 80 {print; ++err} END {exit err}' $TEMPFILE
 
 log_pass "zfs shows a usage message when run as a user"