fix: suppress fastjson2 Unsafe deprecation warnings on Java 23+

[fglock]

Summary

• Add --sun-misc-unsafe-memory-access=allow JVM option to suppress warnings from fastjson2 using deprecated sun.misc.Unsafe methods
• Flag is only added on Java 23+ (JEP 471), since the option does not exist in Java 22
• Updated both jperl (Unix) and jperl.bat (Windows) launchers

Problem

On Java 23+, running ./jperl -MJSON -E 'say encode_json({hello => "world"})' shows warnings:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::arrayBaseOffset has been called by com.alibaba.fastjson2.util.JDKUtils
WARNING: Please consider reporting this to the maintainers of class com.alibaba.fastjson2.util.JDKUtils
WARNING: sun.misc.Unsafe::arrayBaseOffset will be removed in a future release

Solution

Detect Java version at runtime and add the suppression flag only when >= 23.

Test plan

• Tested on Java 24: no warnings, output is {"hello":"world"}
• Should be tested on Java 22 to verify no errors from unknown flag

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