test-clone: fix some instability in pooled clone race condition test
Healthy output (one log file mentioning "existing pooled" and one
mentioning "new pooled") will now print in a stable order, but
unhealthy output will print some sort of error.
This reduces the flakiness of the test from 55% to 38%. My next patch
makes it completely stable.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown