run-tests: make it possible to nest conditionals This is not that hard to implement and makes our life easier on a regular basis.

dirstate-v2: don't mmap the data file when on NFS `mmap` on NFS will trigger a SIGBUS when the mmap'ed file is deleted, which wouldn't work in our case. Also, the performance advantage of using mmap on NFS is debatable at best.

rust-dirstate: trace append/no append to help debugging

rust: add debug log about skipping dirstate update

test-dirstate: use more robust method to trigger a data-file append The previous method was fragile and somewhat flaky on fast machines.

transaction: tests we don't overwrite bookmark activation on abort We actually do not! Great.

transaction: tests we don't overwrite updates on abort spoiler: we do… /o\

transaction: tests we don't overwrite branch changes on abort We actually do not! Great. …Why are doing a backup of the `branch` files at transaction creation then‽

transaction: tests we don't overwrite tracking to changed file on abort spoiler: we do…

transaction: the base of a new test file checking transaction abort issue See inline documentation for details. See other changesets for actual cases.