… non-scalar (romainneutron)

This PR was merged into the 4.1-dev branch.

Discussion
----------

[VarDumper] Allow VarDumperTestTrait expectation to be non-scalar

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

At the moment, when using the `VarDumperTestTrait` in unit test, expecting data object is as follow:

```php
class Toto
{
    private $foo;

    public function __construct($foo)
    {
        $this->foo = $foo;
    }
}

class MyTest extends \PHPUnit_Framework_TestCase
{
     use Symfony\Component\VarDumper\Test\VarDumperTestTrait;

    public function dummyTest()
    {
        $expected = <<<EOEXPECTED
Profiler\Tests\Model\CallGraph\Toto {
  -foo: "baz"
}
EOEXPECTED;

        $this->assertDumpEquals($expected, new Toto('baz'));
    }
}
```

The same test could be easily written like this with this change:

```php
    public function dummyTest()
    {
        $this->assertDumpEquals(new Toto('baz'), new Toto('baz'));
    }
```

Commits
-------

6b5ab90 [VarDumper] Allow VarDumperTestTrait expectation to be non-scalar