tests: tests for revlog version and flags loading We didn't have explicit test coverage of these branches. Better late than never.

perf: allow to clear the obsstore in 'perfvolatilesets' Loading the obsstore can become a large part of the time necessary to compute the important volatile set. We add a flag purging all known obsstore related data. For example, computing the 'bumped' set currently requires reading the full obsstore, so timing greatly differ with or without that flag: Without: ! bumped ! wall 0.005047 comb 0.000000 user 0.000000 sys 0.000000 (best of 446) With: ! bumped ! wall 0.512367 comb 0.510000 user 0.480000 sys 0.030000 (best of 15)

obsolete: test an important corner case Receiving markers affecting changeset we'll receives later is legitimate and not so uncommon case. Working on cache highlighted that this was only testing in the evolve extension. We add a test for this case in core.