rebase: move working parent and bookmark for obsoleted revs (BC)
Previously, obsoleted revs with successors in destination are completely
ignored. That caused some inconvenience when working copy is obsoleted. Most
commands avoid working copy being obsoleted, but `hg pull` is an exception.
This patch makes rebase able to move bookmarks or working parent for those
obsoleted revs. It does so by keeping the obsoleted revs in `state` and
marking them as "skipped, rebased to desired destination" during run-time.
This reverts part of the behavior change of
3b7cb3d17137 and D24.
Differential Revision: https://phab.mercurial-scm.org/D527
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL