testlib: add a small scrip to help process to synchronise using file...
testlib: add a small scrip to help process to synchronise using file
Creating and waiting for files is a robust way to synchronise two processes
running concurrently. We already use this approach in various tests. I am adding
a official script to do so before adding more usage of this.
Differential Revision:
https://phab.mercurial-scm.org/D8189