tests: give more room for slowness in test-run-tests.t
The test expected any run-test.py run to end in less than 10 seconds. On slower
loaded CI machine, this gets slower than that. We give a bit more room to the
regexp.
Set up
$ hg init repo
$ cd repo
Try to import an empty patch
$ hg import --no-commit - <<EOF
> EOF
applying patch from stdin
abort: stdin: no diffs found
[255]
No dirstate backups are left behind
$ ls .hg/dirstate* | sort
.hg/dirstate