Avoid race in CompUnit::PrecompilationStore::File.
Avoid race in CompUnit::PrecompilationStore::File.

Allow duplicate work if that should ever happen, and just bind the
result.

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