patch applied (testsuite): Add a slightly more robust concurrent I/O test

[Simon Marlow]

Mon Feb 18 02:22:31 PST 2008  Simon Marlow <simonmar at microsoft.com>
  * Add a slightly more robust concurrent I/O test
  also disable concio001, which is too unreliable

    M ./tests/ghc-regress/lib/IO/all.T -2 +4
    A ./tests/ghc-regress/lib/IO/concio002.hs
    A ./tests/ghc-regress/lib/IO/concio002.stdout