RFR: 8344078: Remove security manager dependency in java.nio [v3]

[Naoto Sato]

On Sat, 16 Nov 2024 00:30:34 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Expunge the use of the `SecurityManager`, `AccessController`, and the like from the `java.nio` and `sun.nio` package hierarchies.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8344078: Address reviewer comments

Looks good for those two Charset related files.

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PR Review: https://git.openjdk.org/jdk/pull/22132#pullrequestreview-2440005589