Micro-optimize code to get first item of array

I finally chose to apply it as I think it is clearer.

Author: vlakoff

system/Database/Query.php

@@ -281,7 +281,14 @@ protected function compileBinds()
 
         $binds = is_array($this->binds) ? $this->binds : [$this->binds];
 
-        if (is_int(key(array_slice($binds, 0, 1)))) {
+        $array_is_list = null;
+
+        foreach ($binds as $key => $value) {
+            $array_is_list = is_int($key);
+            break;
+        }
+
+        if ($array_is_list) {
             $bindCount = count($binds);
             $ml        = strlen($this->bindMarker);