Select memcached rand fn based on *_WP_ORG_MODE

We use mt_rand for memcached because CSPRNGs
can have lag spikes and we simply gain nothing
from the cryto properties. But wordpress.org
prohibits mt_rand, so we use wp_rand for WP.org
only.

Author: john-shaffer

src/Memcached.php

@@ -45,7 +45,18 @@ public static function getRandomServer(
             $total_weight += $s['weight'] ?? 1;
         }
 
-        $rand = mt_rand( 1, $total_weight );
+        if ( defined( 'STATIC_DEPLOY_WP_ORG_MODE' ) && STATIC_DEPLOY_WP_ORG_MODE ) {
+            $rand = wp_rand( 1, $total_weight );
+        } else {
+            $rand = mt_rand( 1, $total_weight );
+        }
+
+        if ( ! defined( 'STATIC_DEPLOY_WP_ORG_MODE' ) || ! STATIC_DEPLOY_WP_ORG_MODE ) {
+            $rand = mt_rand( 1, $total_weight );
+        } else {
+            $rand = wp_rand( 1, $total_weight );
+        }
+
         $current = 0;
 
         foreach ( $servers as $server ) {