Description:
------------
If I enter the URL like this "/path?#"
The `parse_url()` function always return fragment and query array key while previous versions of PHP like 5.x, 7.x doesn't return these value if not exists.

Expected result:
----------------
array(
    'path' => '/path',
);

Actual result:
--------------
array(
    'path' => '/path',
    'query' => '',
    'fragment' => '',
);