Restore dotted list evaluation on REPL

JSCL REPL couldn't evaluate dotted list (any more?):
```lisp
CL-USER> '(1 2)
(1 2)
CL-USER> '(1 . 2)
Error occurred
```
That's mainly because when compiler tries to ```dump-cons``` dotted list,
it calls ```copy-list```, while ```copy-list``` doesn't support dotted list in JSCL
for now.