tests/test-empty-dir.t

match: drop unnecessary wrapping of regex in group

It seems the regexes have been wrapped in an unnamed group since
b6c42714d900 (Add locate command., 2005-07-05). In that commit, the
grouping was needed because there was a "head" ('^') added before the
group and a "tail" (os.sep) added after it. It seems the head was
moved inside the group in 1c0c413cccdd (Get add and locate to use new
repo and dirstate walk code., 2005-07-18) and the tail was moved
inside the group in 89985a1b3427 (Clean up walk and changes code to
use normalised names properly., 2005-07-31), So it seems to me that
we've carried around the unnecessary group for 13 years. This patch
removes it.

Differential Revision: https://phab.mercurial-scm.org/D5352

  $ hg init

  $ echo 123 > a
  $ hg add a
  $ hg commit -m "first" a

  $ mkdir sub
  $ echo 321 > sub/b
  $ hg add sub/b
  $ hg commit -m "second" sub/b

  $ cat sub/b
  321

  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cat sub/b 2>/dev/null || echo "sub/b not present"
  sub/b not present

  $ test -d sub || echo "sub not present"
  sub not present