fix special-case recreation of *::

fix special-case recreation of *::

If *:: is called for then as a special case it is looked up as
$::{"main::"}.  If $::{"main::"} has been deleted, then that hash entry
is recreated.  But formerly it was only recreated as an undef scalar,
which broke things relying on glob lookup returning a glob.  Now in
that special case the recreated hash entry is initialised as a glob,
and populated with the customary recursive reference to the main stash.
Fixes [perl #129869].