RFR: 8315968: Consolidate java.util.Digits and StringLatin1::PACKED_DIGITS [v7]

[温绍锦]

On Mon, 11 Sep 2023 18:57:58 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> If this PR is split into two PRs, the other two PRs I submitted #15658 #15555 cannot be based on this PR.
>
> I agree, do the package move separate from the refactoring. 
> The other PRs can wait a bit or be committed as is and take part in the refactoring later. 
> One step at a time please.

Refactoring of stringSize has been restored

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PR Review Comment: https://git.openjdk.org/jdk/pull/15651#discussion_r1322178873