tests/test-revlog-packentry.t

rebase: change "editform" to distinguish merge commits from others

"editform" argument for "getcommiteditor" is decided according to the
format below:

  EXTENSION[.COMMAND][.ROUTE]

  - EXTENSION: name of extension
  - COMMAND: name of command, if there are two or more commands in EXTENSION
  - ROUTE: name of route, if there are two or more routes in COMMAND

This patch newly adds "merge" as ROUTE, to distinguish merge commits
from other.

This patch passes bool as "ctxorbool" to "mergeeditform", because
working context has always 2 parents at this point. Dropping the
second parent of non-merging commits is executed in "concludenode".

Unlike other patches in this series (e.g. for "hg commit"), this patch
doesn't add "normal.normal"/"normal.merge" style ROUTEs, because there
is no "merge" case in "collapse" ROUTE.

  $ hg init repo
  $ cd repo

  $ touch foo
  $ hg ci -Am 'add foo'
  adding foo

  $ hg up -C null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

this should be stored as a delta against rev 0

  $ echo foo bar baz > foo
  $ hg ci -Am 'add foo again'
  adding foo
  created new head

  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       0  .....       0 b80de5d13875 000000000000 000000000000 (re)
       1         0      24  .....       1 0376abec49b8 000000000000 000000000000 (re)

  $ cd ..