[Tests] Expect twig composer-based set in SetManagerTest

[TomasVotruba]

rector-symfony's TwigSetProvider now provides a twig/composer-based.php set constrained to twig/twig >=1.12, on top of the 7 version-pinned sets. Every twig fixture project in SetManagerTest installs twig >=1.12, so the composer-based set is matched for all of them.

-        $this->assertCount(7, $twigComposerTriggeredSet);
+        $this->assertCount(8, $twigComposerTriggeredSet);

-        yield [__DIR__ . '/Fixture/project-twig-20', [realpath(TwigSetList::TWIG_20)]];
+        yield [
+            __DIR__ . '/Fixture/project-twig-20',
+            [realpath(TwigSetList::COMPOSER_BASED), realpath(TwigSetList::TWIG_20)],
+        ];

Test-only change; vendor/bin/phpunit is green with it.