Bug 1038165 - [Callscreen] check displayed before connecting to SCO

Can you merge those two tests like this (with the title change):
 ```javascript
test('should never connect bluetooth SCO', function() {
  var connectScoSpy = this.sinon.spy(
    MockBluetoothHelperInstance, 'connectSco');
  CallsHandler.switchToDefaultOut();
  assert.isTrue(connectScoSpy.notCalled);
  CallsHandler.switchToDefaultOut(true /* do not connect */);
  assert.isTrue(connectScoSpy.notCalled);
});
```
I think this will be more readable than two tests with the same name.