Merge branch 'ps/ref-tests-update-even-more'

More tests that are marked as "ref-files only" have been updated to
improve test coverage of reftable backend.

* ps/ref-tests-update-even-more:
  t7003: ensure filter-branch prunes reflogs with the reftable backend
  t2011: exercise D/F conflicts with HEAD with the reftable backend
  t1405: remove unneeded cleanup step
  t1404: make D/F conflict tests compatible with reftable backend
  t1400: exercise reflog with gaps with reftable backend
  t0410: convert tests to use DEFAULT_REPO_FORMAT prereq
  t: move tests exercising the "files" backend

diff --cc t/t1400-update-ref.sh
Simple merge