Resets/initializes the history of calls to the test toolkit functions.
function imageTestReset() {
// Keep track of calls to these operations
$results = array(
'load' => array(),
'save' => array(),
'settings' => array(),
'resize' => array(),
'rotate' => array(),
'crop' => array(),
'desaturate' => array(),
);
\Drupal::state()
->set('image_test.results', $results);
}