Perl6::Ops is backend-specific.
Add a partly translated Perl6::Ops for JVM.

We'll have some Perl 6 specific ops in JVM land. This translates the
mappings, though of course the ops all still need implementing. This
just means we can compile things that refer to them.
nqp::concat => nqp::concat_s

They are just synonyms by now.
Add Perl6::Actions to the JVM build.