Perl 5.16.3 is sporadically failing the dist/IO/t/io_unix.t
on my mention when run with TEST_JOBS > 1, but consistently
passes without that. Adding a flag to Releases.yaml to allow
this to be coordinated properly.
This is not yet complete; what remains is the ability to generate
the final patch, the one that patches patchlevel.h (and thus
lists the locally applied patches in perl -V / Config.pm).
This requires downloading the proper patchlevel.h for each version
and generating a patch in generate.pl.
