D212: tests: demonstrate crash when trying to rebase merge without its parents

[quark (Jun Wu)]

quark accepted this revision.
quark added a comment.


  Thanks for this case too!

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D212

To: martinvonz, #hg-reviewers, quark
Cc: quark, mercurial-devel