Fix CurrentThreadScheduler error handling
Fix CurrentThreadScheduler error handling

It is used as a type object rather than an instance in quite some
tests, and so very possibly in the wild too. So make sure that it
doesn't explode due to trying to look up an error handler from a
type object.

Gnouc/rakudo,softmoth/rakudo,raydiak/rakudo,labster/rakudo,tbrowder/rakudo,nbrown/rakudo,labster/rakudo,salortiz/rakudo,tbrowder/rakudo,rakudo/rakudo,raydiak/rakudo,tony-o/rakudo,tony-o/rakudo,Gnouc/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,rakudo/rakudo,lucasbuchala/rakudo,usev6/rakudo,tbrowder/rakudo,nbrown/rakudo,lucasbuchala/rakudo,Gnouc/rakudo,usev6/rakudo,rakudo/rakudo,softmoth/rakudo,usev6/rakudo,nbrown/rakudo,salortiz/rakudo,awwaiid/rakudo,Gnouc/rakudo,tony-o/rakudo,usev6/rakudo,rakudo/rakudo,awwaiid/rakudo,tbrowder/rakudo,Gnouc/rakudo,rakudo/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,awwaiid/rakudo,tbrowder/rakudo,salortiz/rakudo,jonathanstowe/rakudo,salortiz/rakudo,labster/rakudo,nbrown/rakudo,salortiz/rakudo,tony-o/rakudo,softmoth/rakudo,jonathanstowe/rakudo,labster/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,jonathanstowe/rakudo,nbrown/rakudo,labster/rakudo,softmoth/rakudo,salortiz/rakudo,MasterDuke17/rakudo,awwaiid/rakudo,MasterDuke17/rakudo,tony-o/rakudo,awwaiid/rakudo,tony-o/rakudo,lucasbuchala/rakudo,nbrown/rakudo,raydiak/rakudo,rakudo/rakudo,jonathanstowe/rakudo,softmoth/rakudo,raydiak/rakudo,usev6/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,labster/rakudo