Update p5-Test-Simple to 0.98.

Changes from previous:
0.98  Wed, 23 Feb 2011 14:38:02 +1100
    Bug Fixes
    * subtest() should not fail if $? is non-zero. (Aaron Crane)

    Docs
    * The behavior of is() and undef has been documented. (Pedro Melo)

0.97_01  Fri Aug 27 22:50:30 PDT 2010
    Test Fixes
    * Adapted the tests for the new Perl 5.14 regex stringification.
      (Karl Williamson) [github 44]

    Doc Fixes
    * Document how to test "use Foo ()". (Todd Rinaldo) [github 41]

    Feature Changes
    * subtest() no longer has a prototype.  It was just getting in the way.
      [rt.cpan.org 54239]
    * The filehandles used by default will now inherit any filehandle
      disciplines from STDOUT and STDERR IF AND ONLY IF they were applied
      before Test::Builder is loaded.  More later. [rt.cpan.org 46542]

(hiramatsu)