tests: disable revlog compression in test-generaldelta.t (issue6867) The revlog compression makes a lot of numbers unstable. Since checking revlog compression is not the goal of this test, we disable the compression to get stable numbers. This should avoid wasting more time on this kind of changes in the future.

test-general-delta: actually test optimize-delta-parent-choice=no Since the configuration was not explicit, the case stopped testing what it intended to test when the default value changed.

test-chg: stabilize the log checking The "worker process exited" line have been making the CI flaky for a long time. Lets sort this out.

tests: fix test-patchbomb-tls.t instability The flakiness on chg is caused by a client that exit faster than the server output log. So actively wait for the server to issue the expected output (with a small timeout)

test-lock: use synchronisation file instead of sleep This will prevent the test to be flaky on load.

branchcache: use update_disk to refresh 'served' and 'served.hidden' The `update_disk` method is dedicated to this kind of usecase. Now that the writting patterns are more consistent, we can use it to warm these two important cache. I am dropping the first comment about "refreshing all the others" because it is false. If a branchmap already exist for "served", none of the subset will be updated.