RFR: 8298416: Console should be declared `sealed` [v3]

[Jaikiran Pai]

On Wed, 14 Dec 2022 17:35:46 GMT, Naoto Sato <naoto at openjdk.org> wrote:

>> `Console` class now has a couple of internal subclasses within `java.io` package. It should be `sealed` and subclasses be declared in the `permits` clause. The implementation resided in `Console` class is separated into `ConsoleImpl` class.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Moved echo() to ConsoleImpl, clean-ups

Marked as reviewed by jpai (Reviewer).

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PR: https://git.openjdk.org/jdk/pull/11615