Bug970187, CDMA-3way calls

https://bugzilla.mozilla.org/show_bug.cgi?id=970187
Create only one connection for this suite then adjust it's |voice| property in the various tests; there's no need to rebuild the connection everytime. In fact by default the mock should have a connection already setup so you can probably get away with:
```
MockNavigatorMozMobileConnections[0].voice = { ... };
```