RFR: 8260338: Some fields in HaltNode is not cloned

[Tobias Hartmann]

On Mon, 25 Jan 2021 01:53:56 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

> I got strange log as following. Contents in `CodeString` is garbled. It seems not to be initialized.
> 
> [3.155s][trace][codestrings ] Created CodeString [ dｴ・] (0x7f3804a150)
> 
> `HaltNode` has two fields - `_reachable` and `_halt_reason`, but they would not be cloned at Node::clone.

@YaSuenag For future PRs, please wait for at least 24 hours before integrating a non-trivial change. A change is only considered trivial if it's explicitly stated by a reviewer in the PR (see **trivial** in [OpenJDK Developers’ Guide](https://openjdk.java.net/guide/#glossary). Thanks.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2213