RFR: 8293499: Provide jmod --compress option [v5]

[Mandy Chung]

On Tue, 13 Sep 2022 17:35:45 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Here is where we get into a minor pickle. We currently default to `Deflater.DEFAULT_COMPRESSION`, which is `-1`, and which is handled inside `zlib` as `6`. We can say `zip-6` here is the default, but that would be stale if zlib ever updates its default. Still fair to say `zip-6` here, or?
>
> Actually, nevermind. Let's just put the defacto `6` into `jmod` defaults, and use it. See new commit.

Sounds good as the implementation sets 6 as the default.  The new commit looks good.

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PR: https://git.openjdk.org/jdk/pull/10213