tests/test-absorb-strip.t

logexchange: convert paths to unix when detecting the active path

This fixes the problem in the tests[1] where Windows was showing the whole path
as the remotename for local repositories.

Somebody with a better understanding of this extension should probably take a
deeper look.  There may be other cases that need to be converted- specifically
the `elif not instance` and the missing `else` cases in activepath().  I also
noticed when adding debug prints that the absolute path is stored in the file,
probably not normalized.  (It's wrapped up in $TESTTMP.)

[1] https://buildbot.mercurial-scm.org/builders/Win7%20x86_64%20hg%20tests/builds/1042/steps/run-tests.py%20%28python%202.7.13%29/logs/stdio

Do not strip innocent children. See https://bitbucket.org/facebook/hg-experimental/issues/6/hg-absorb-merges-diverged-commits

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > absorb=
  > drawdag=$TESTDIR/drawdag.py
  > EOF

  $ hg init
  $ hg debugdrawdag << EOF
  > E
  > |
  > D F
  > |/
  > C
  > |
  > B
  > |
  > A
  > EOF

  $ hg up E -q
  $ echo 1 >> B
  $ echo 2 >> D
  $ hg absorb -a
  saved backup bundle to * (glob)
  2 of 2 chunk(s) applied

  $ hg log -G -T '{desc}'
  @  E
  |
  o  D
  |
  o  C
  |
  o  B
  |
  | o  F
  | |
  | o  C
  | |
  | o  B
  |/
  o  A