Fix 'is export' on constants assigned to routines
Fix 'is export' on constants assigned to routines

The 'is export' exception catchall was higher precedence than the
constant exporting candidate in the case of Routine. This patch makes
`constant $sub is export = sub { ... }` take the same path as
`sub foo is export { ... }` while preserving the constant variable's
symbol.

Fixes "Can't use unknown trait 'is export' in a ... declaration" for
statements like:

constant $constant-regex is export =  /fo*/;
constant &constant-sub   is export  = sub { "win" };

Zoffix++ for the patch

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