[perl #126241] operator names need to be valid, parsable Perl

[Larry Wall via RT]

nqp fix in a79e4abbe60d28f59b451416e7946ee433db7199
rakudo fix in 091637fd5ace48a0835fc8af786f2caa372381cf
roast fix in dc3e1335232bb617b42d335ddbcc42be0a9dedaa