RFR: 8357995: Use "stdin.encoding" for reading System.in with InputStreamReader/Scanner [core] [v5]

[Volkan Yazici]

On Thu, 5 Jun 2025 10:13:24 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> Passes the `Charset` read from the `stdin.encoding` system property while creating `InputStreamReader` or `Scanner` instances for `System.in`.
>> 
>> `stdin.encoding` is a recently added property for Java 25 in [JDK-8350703](https://bugs.openjdk.org/browse/JDK-8350703). Employing it throughout the entire code base is addressed by the parent ticket [JDK-8356893](https://bugs.openjdk.org/browse/JDK-8356893). JDK-8357995 this PR is addressing is a sub-task of JDK-8356893 and is concerned with only areas related to core libraries.
>
> Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Improve code style
>   
>   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>

test/jdk/javax/script/MyContext.java line 52:

> 50:         engineScope = new SimpleBindings();
> 51:         globalScope = null;
> 52:         reader = new InputStreamReader(System.in, System.getProperty("stdin.encoding"));

I will revert this change, since

1. AFAICT, this file is not used anymore
2. Neither `std{out,err}.encoding` were used while creating `PrintWriter`s below

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PR Review Comment: https://git.openjdk.org/jdk/pull/25544#discussion_r2139786341