Fix spurious spectest failures caused by ephemeral files
Fix spurious spectest failures caused by ephemeral files

The failing S11 tests do use lib "." while other tests create short lived files
like getout-13575-776701.in. Those files disappear between the .dir that lists
them and the .open leading to:
"Failed to open file /home/nine/rakudo/getout-13575-776701.in: no such file or
directory"
Fix by only reading Perl6 module files and handling failures to do so
gracefully. Should improve performance, too.

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