Description:
------------
When using the built-in server files are cached and don't reflect updates unless the server is restarted.

Test script:
---------------
1) Save index.php to a directory:

```
<?php
echo 'hello, world';
```

2) Run the server in the directory where index.php is located:

php -S localhost:7777

3) Go to http://localhost:7777/index.php in your browser, output will be "Hello world"

4) Change the echo statement in index.php to output something else and save the file

5) Refresh http://localhost:7777/index.php, output will still be "Hello world" instead of the new echo statement

Expected result:
----------------
The server will reflect the code in the file without being restarted

Actual result:
--------------
The output is always the same