Tweak error/exception handler registration

Author: nicolas-grekas

EventListener/DebugHandlersListener.php

@@ -57,7 +57,7 @@ public function __construct(?callable $exceptionHandler = null, ?LoggerInterface
             $deprecationLogger = $fileLinkFormat;
         }
 
-        $handler = set_exception_handler('is_int');
+        $handler = set_exception_handler('var_dump');
         $this->earlyHandler = \is_array($handler) ? $handler[0] : null;
         restore_exception_handler();
 
@@ -84,7 +84,7 @@ public function configure(?object $event = null)
         $this->firstCall = $this->hasTerminatedWithException = false;
         $hasRun = null;
 
-        $handler = set_exception_handler('is_int');
+        $handler = set_exception_handler('var_dump');
         $handler = \is_array($handler) ? $handler[0] : null;
         restore_exception_handler();