tests/test-dirstate-race.t

largefiles: use 'dirstate.dirs()' for 'directory pattern' relation check

original implementation queries whether specified pattern is related
or not to largefiles in target context by 'dirstate.__contains__()'.

but this can't recognize 'directory pattern' correctly, so this patch
uses 'dirstate.dirs()' for it.

this patch uses dirstate instead of lfdirstate in 'working' route
(second patch hunk for 'hgext/largefiles/reposetup.py'), because
'dirs()' information may be already built for dirstate but not yet for
lfdirstate at this point. this prevents lfdirstate from building up
and having 'dirs()' information.

  $ 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