Reset the peak memory usage for each cronjob in CronjobScheduler::executeCronjobs()

The same reasoning as with the background jobs applies. The `executeCronjobs()`
method is the method that performs several a-priori unknown cronjobs and is
only used for purpose-built controllers.

Author: TimWolla

wcfsetup/install/files/lib/system/cronjob/CronjobScheduler.class.php

@@ -60,6 +60,13 @@ public function executeCronjobs()
             SessionHandler::getInstance()->changeUser(new User(null), true);
 
             foreach ($cronjobEditors as $cronjobEditor) {
+                // Reset the memory usage for each cronjob, allowing to measure each individual
+                // cronjob's memory usage without a memory-heavy cronjob skewing the numbers for
+                // the following cronjobs.
+                if (\PHP_VERSION_ID >= 80200) {
+                    \memory_reset_peak_usage();
+                }
+
                 // mark cronjob as being executed
                 $cronjobEditor->update([
                     'state' => Cronjob::EXECUTING,