Description:
------------
pathinfo() can't handle relative path like /dir/subdir1/../subdir2/file.ext

Reproduce code:
---------------
$path_parts = pathinfo('/dir/subdir1/../subdir2/file.ext');
print_r($path_parts);

Expected result:
----------------
Array ( 
[dirname] => /dir/subdir2
[basename] => index.html 
[extension] => html
)

Actual result:
--------------
Array ( 
[dirname] => /dir/subdir1/../subdir2
[basename] => index.html 
[extension] => html
)