ref: 8d9a4e15029b23e367b5ae6a399f22e4cf5f0c9f dir: /sys/src/cmd/diff/test/merge-t3.expected/
1 2 3 4 <<<<<<<<<< merge-t3.l y ========== original 5 ========== merge-t3.r x >>>>>>>>>> 6 7 8 9 10