Merge branch '5.4' into 6.4

* 5.4:
  preserve the file modification time when mirroring directories
  use local PHP web server to test HTTP stream wrappers

Filesystem.php

@@ -74,6 +74,9 @@ public function copy(string $originFile, string $targetFile, bool $overwriteNewe
                 // Like `cp`, preserve executable permission bits
                 self::box('chmod', $targetFile, fileperms($targetFile) | (fileperms($originFile) & 0111));
 
+                // Like `cp`, preserve the file modification time
+                self::box('touch', $targetFile, filemtime($originFile));
+
                 if ($bytesCopied !== $bytesOrigin = filesize($originFile)) {
                     throw new IOException(sprintf('Failed to copy the whole content of "%s" to "%s" (%g of %g bytes copied).', $originFile, $targetFile, $bytesCopied, $bytesOrigin), 0, null, $originFile);
                 }