contrib/wix/defines.wxi

tests: clean up test-rollback.t

The last comment is on the last file line and is useless, seems
like it was introduced in 8fdc11fec6ae during unification.

<Include>

  <?if $(var.Platform) = "x64" ?>
    <?define IsX64 = yes ?>
  <?else?>
    <?define IsX64 = no ?>
  <?endif?>

</Include>