tests/test-dirstate-race.t

pathcomplete: remove ambiguous entries for sole completion on a directory

Previously, directories were added with the trailing slash and, if there was
only one completion, then another ambiguous entry was created using '.', as
follows:

$ hg rm mer<TAB>
mercurial/./  mercurial//

This was added in fa6d5c62f3bd (though, some logic existed before that) to work
around bash completion adding a space after the sole entry because we treated
directories and files the same. We no longer do that now so we remove this
unneeded code.

Tests have been updated to match this new behavior.

  $ hg init
  $ echo a > a
  $ hg add a
  $ hg commit -m test

Do we ever miss a sub-second change?:

  $ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
  >     hg co -qC 0
  >     echo b > a
  >     hg st
  > done
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a