rust-threads: force Rayon to respect the worker count in config As per the inline comment, this is a workaround because Rust code does not yet know how to read config files. Differential Revision: https://phab.mercurial-scm.org/D7610

remotefilelog: remove the `ensurestart` usage The option does not seems to do what we want since it does not wait on the background process actually starting (eg: taking the lock). And the race have been dealt with another way anyway. This effectively back out changeset 2c74337e6483. Differential Revision: https://phab.mercurial-scm.org/D7590

remotefilelog: remove most of the debugwait* command in the tests Since we use a dedicated developer config, we do not need them anymore. Differential Revision: https://phab.mercurial-scm.org/D7589

remotefilelog: use the correct redirection in tests The test were using '2>%1' which just redirect stderr in the "%1" file. The intend was '2>&1' which redirect stderr on stdin. This impact tests because some commit were picking up this '%1' files. Differential Revision: https://phab.mercurial-scm.org/D7588

remotefilelog: remove most sleep in tests Now that we removed most of the races, we can remove the infamous sleeps. Differential Revision: https://phab.mercurial-scm.org/D7587

remotefilelog: have command wait for background task in the tests We leverage the feature introduced in the two previous commit to have the main command wait for the background task to be finished before returning. All test still pass and instability seems to have gone away. Most of the sleep and explicit wait are now useless and will be cleaned up in later changesets. Differential Revision: https://phab.mercurial-scm.org/D7586