RFR: 8344856: Remove calls to SecurityManager and doPrivileged in sun.net.www.protocol.ftp.FtpURLConnection after JEP 486 integration [v2]

[duke]

On Wed, 27 Nov 2024 09:22:54 GMT, Volkan Yazıcı <duke at openjdk.org> wrote:

>> This change set, addressing [8344856](https://bugs.openjdk.org/browse/JDK-8344856), removes `SecurityManager` and friends from `sun.net.www.protocol.ftp.FtpURLConnection`. This is the only leftover from `SM` cleanup in the subclasses of `URLConnection` in the `sun.net` package. Successful `tier1..3` CI runs on b02813b048ec63479c49e74ca6326a00409dd34f are shared in the ticket.
>
> Volkan Yazıcı has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove redundant suppression

@vy 
Your change (at version 9b30465700f5a9b0058c21b62b5c789ce6c80e44) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/jdk/pull/22407#issuecomment-2503728779