bug #32902 [PhpUnitBridge] Allow sutFqcnResolver to return array (VincentLanglet)

This PR was merged into the 3.4 branch.

Discussion
----------

[PhpUnitBridge] Allow sutFqcnResolver to return array

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #...
| License       | MIT
| Doc PR        |

Phpunit handle multiple covers annotation:
```
/**
 * @Covers ClassOne
 * @Covers ClassTwo
 */
```

The coverage solver was only allowed to return `ClassOne` or `ClassTwo` since it was transformed to `[ClassName]`. Returning `[ClassOne, ClassTwo]` was transform to [[ClassOne, ClassTwo]]` which was creating an error with phpunit. This PR fixed this case.

Commits
-------

1451c0b915  Allow sutFqcnResolver to return array

Author: nicolas-grekas

Legacy/CoverageListenerTrait.php

@@ -76,7 +76,7 @@ public function startTest($test)
         $cache = $r->getValue();
         $cache = array_replace_recursive($cache, array(
             \get_class($test) => array(
-                'covers' => array($sutFqcn),
+                'covers' => \is_array($sutFqcn) ? $sutFqcn : array($sutFqcn),
             ),
         ));
         $r->setValue($testClass, $cache);