tests: demonstrate that copy info in changeset gets lost on amend When copy information is stored in changesets, it gets lost on amend. We didn't notice that until now because our users at Google have the config set to `compatibility`, which means copy information is stored in both changeset and filelogs. Differential Revision: https://phab.mercurial-scm.org/D12386

ci: use the `v1.0` flavor of the docker images in the CI This new versioning will help us to maintain backward compatibility in the docker image. This will be useful to deal with mismatch between default/stable in version and the re-run CI on older changesets in the future. Once this changeset land on stable, we will have to merge it in default. Then we can start make backward incompatible changes in a new image version. Differential Revision: https://phab.mercurial-scm.org/D12388

rust-status: cap the number of concurrent threads to 16 During benchmarking it was determined that the use of more threads is very advantageous... until we use more than 16. This is most likely due to some resource contention (thrashing, etc.). Until we have time to figure out and fix the underlying cause, let's just cap at 16 threads. Differential Revision: https://phab.mercurial-scm.org/D12384