Issue #3258507 - rather than str_replace the entire placeholder array, replace...

Issue #3258507 - rather than str_replace the entire placeholder array, replace one at a time in the reverse order they were added. This benchmarks faster too for some reason.

src/EventSubscriber/MinifyHTMLExit.php

@@ -184,7 +184,9 @@ class MinifyHTMLExit implements EventSubscriberInterface {
 
     // Restore all values that are currently represented by a placeholder.
     if (!empty($this->placeholders)) {
-      $this->content = str_replace(array_keys($this->placeholders), array_values($this->placeholders), $this->content);
+      foreach (array_reverse($this->placeholders, TRUE) as $placeholder => $value) {
+        $this->content = str_replace($placeholder, $value, $this->content);
+      }
     }
   }