use array_replace_recursive instead of array_merge_recursive

Author: januszmk

src/Symfony/Component/BrowserKit/HttpBrowser.php

@@ -82,11 +82,7 @@ private function getBodyAndExtraHeaders(Request $request, array $headers): array
         $fields = $request->getParameters();
 
         if ($uploadedFiles = $this->getUploadedFiles($request->getFiles())) {
-            if (\count($fields) !== \count($fields, \COUNT_RECURSIVE)) {
-                $part = new FormDataPart(array_merge_recursive($fields, $uploadedFiles));
-            } else {
-                $part = new FormDataPart(array_merge($fields, $uploadedFiles));
-            }
+            $part = new FormDataPart(array_replace_recursive($fields, $uploadedFiles));
 
             return [$part->bodyToIterable(), $part->getPreparedHeaders()->toArray()];
         }