Use full JSON stringify when printing results in DRY mode

Otherwise can shorten some values (in this case arrays of two numbers)
```
saving snapshot "checks behavior of binary function add 1" for
file src/data-driven-spec.js
{ name: 'add',
behavior:
[ { given: [Object], expect: 3 },
{ given: [Object], expect: 4 },
{ given: [Object], expect: 0 },
{ given: [Object], expect: 21 } ] }
✓ checks behavior of binary function add
```

Start in src/data-driven-spec.js and trace how results are printed in DRY mode. Reproduce the snapshot output shown in the issue, then verify that arrays and nested values are rendered with full JSON stringification rather than shortened placeholders.

Written by the indexing model from the issue text.