Revert "Rewritten device groups (including static) (#10295)" (#10340)

This reverts commit cfc51d51f5.

includes/helpers.php

@@ -86,23 +86,3 @@ if (!function_exists('set_debug')) {
         return $debug;
     }
 }
-
-if (!function_exists('array_pairs')) {
-    /**
-     * Get all consecutive pairs of values in an array.
-     * [1,2,3,4] -> [[1,2],[2,3],[3,4]]
-     *
-     * @param array $array
-     * @return array
-     */
-    function array_pairs($array)
-    {
-        $pairs = [];
-
-        for ($i = 1; $i < count($array); $i++) {
-            $pairs[] = [$array[$i - 1], $array[$i]];
-        }
-
-        return $pairs;
-    }
-}