delta-find: gather the condition to blindly use a full snapshot together We are about to make the `if` body bigger, so having only one of them is simpler/

delta-find: initialize the debug information much sooner (when possible) This help us to record debug information in alternative path.

delta-find: fix `parents` round detection We should compare integer with integer, instead of bytes (node).

delta-find: intrduce a `_one_dbg_data` method This helps with the initialisation of the expected debug information.

delta-find: move final debug processing in a `_dbg_process_data` method This will help us making sure we can call the necessary debugging code in alternative codepath.

delta-fine: use the `_debug_search` attribute directly By adjusting the value at creation time, we can avoid the need to use and intermediate variable.

delta-find: move the `gather_debug` logic in a property This will make it simpler to get be reused in multiple places.

tests: check `pulled-delta-reuse-policy=forced` without general delta If general delta is not available, the amount of delta we can reuse at all will be more limited. We check that application still work and does not corrupt the repository.

tree-manifest: allow `debugupgraderepo` to run on tree manifest repo There does not seems to be anything wrong with running the current logic on them. So we remove the limitation.

bundles: clarify streaming v2 bundle usage This seems useful to clarify through the documentation (we were still using debugcreatestreamclonebundle, even though 'hg bundle' is already an option...).