Put all sort arguments in list context

Put all sort arguments in list context

The arguments following the first were using the context the enclosing
function was called in.

sub context { warn qw[void scalar list][wantarray + defined wantarray ] }
sub foo { sort +context, context; print "------\n"; }
foo;
$_ = foo;
[foo];
__END__

Output:

list at - line 1.
void at - line 1.
------
list at - line 1.
scalar at - line 1.
------
list at - line 1.
list at - line 1.
------

Extend the list context to all arguments.