Debugging the result property in a ViewExecutable
Your code works fine for me so perhaps your view has no results?
Anyways, the Drupal log is not really meant to be used for printing variables for debugging purposes. Use an appropriate tool like Devel which has/comes with another module called Kint, enable Kint.
use Drupal\views\ViewExecutable;

/**
 * Implements hook_views_post_execute()
 */
function mymodule_views_post_execute(ViewExecutable $view) {
  kint($view-&gt;result);
}

Flush cache and you'll see this

For more info on how to use Kint, see Welcome to Kint 101