TestDataBuilder does not autopopulate property values unless the type name starts with an uppercase letter.

This gets auto populated:

```
 "date": {
 "type": "Date",
 "required": true
 },
```

whist this doesn't:

```
 "date": {
 "type": "date",
 "required": true
 },
```

Both are valid schema definitions that mean the same thing to Loopback. They should both cause the property value to be auto populated
