largefile: make sure we hold the lock when updating the second dirstate The largefile extension uses a second dirstate file (and object) to track some states. In some situations, it is lazily updated when needed. These operations might not have the lock taken. This means they might conflict and race with other ongoing operations. So we now take the lock to do these operations. This was caught by the next commit.

dirstate: rename `@requires_no_parents_change` too This match the rename of the context manager.

dirstate: rename `@requires_parents_change` to `@requires_changing_parents` This match the rename of the context manager.