Test failures for Type::Params on earlier Perls

[cxw42]

E.g., http://www.cpantesters.org/cpan/report/f9110536-d535-11e9-9066-e374b0ba08e8 .

The package variables are undef at the time they are used.

[cxw42]

The deal was that local @_ was interacting badly with goto &$candidate. Apparently on newer Perls the local @_ wasn't being reverted, or the guard was living through the invocation of $candidate, so everything worked. However, older Perls took seriously perldoc's admonition that goto "los[es] any changes set by local". Therefore, the guard was being called and resetting the package variables before $candidate could run. Removing the local did the job!

Also, for the record, whenever you use a ternary, make sure it has parens before it. The failures in http://www.cpantesters.org/cpan/report/9be5b5be-d648-11e9-99fe-b031dbec7dbf were because

sub foo { }
diag foo ? 'bar' : 'bat';
...
diag foo ? 'baz' : 'quux';

can be interpreted as diag(foo(? 'bar' ... foo ? ...)), where the ?...? is an m?? construct without leading m (prohibited in 5.22+ - https://metacpan.org/pod/Syntax::Construct#??).