When theme registry is overwritten, $info['includes'] is lost.

Bug description:
When theme registry is overwritten, the latter $info['includes'] is lost.

Suppose someA module defines the following hook_theme() function:

function someA_theme()
{
    $path=\drupal::moduleHandler()->getModule("someA")->getPath();
    return [
        'yunke' => [
            'variables' => ['title' => null, 'msg' => null],
            'includes'  => ["$path/someA_a.php","$path/someA_b.php"],
        ],
    ];
}

Another someB module defines the following hook_theme() function:

function someB_theme()
{
    $path=\drupal::moduleHandler()->getModule("someB")->getPath();
    return [
        'yunke' => [
            'variables' => ['title' => null, 'msg' => null],
            'includes'  => ["$path/someB_a.php","$path/someB_b.php"],
        ],
    ];
}

SomeB_theme () is executed after someA_theme(). In the result, someB_a.php and someB_b.php is missing.

This bug comes from:
\Drupal\Core\Theme\Registry::processExtension line 464-473

The fix is as follows:

        if (isset($info['includes'])) {
          foreach ($info['includes'] as $include_file) {
            include_once $this->root . '/' . $include_file;
            if(!in_array($include_file, $result[$hook]['includes']))
            {
                $result[$hook]['includes'][] = $include_file;
            }
          }
        }