isolate only works if isolate is copied into #

[mkromberg]

To reproduce:

 )ns ns1
 )cs ns1
 )copy isolate isolate
 is←isolate.New''
 is.(2+2)

FUTURE ERROR: 86: COMMUNICATIONS FAILURE 1119 ERR_CLOSED : Socket closed whilst receiving data

[mkromberg]

This is a duplicate of #1. It is fixed in v19.0 but should be back-ported to the isolate workspace used by 18.2.