RFR: 8315968: Consolidate java.util.Digits and StringLatin1::PACKED_DIGITS [v17]

[温绍锦]

> Some codes in core libs are duplicated, including:
> java.util.DecimalDigits::DIGITS -> java.lang.StringLatin1.PACKED_DIGITS
> java.util.DecimalDigits::size -> java.lang.Long.stringSize
> 
> We can reduce duplication through JavaLangAccess, which is also needed in other places, such as:
> https://github.com/openjdk/jdk/pull/15555

温绍锦 has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  rebase & resolve DecimalDigits delete and add

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/15651/files
  - new: https://git.openjdk.org/jdk/pull/15651/files/9bccc890..27174f45

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15651&range=16
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15651&range=15-16

  Stats: 52 lines in 3 files changed: 11 ins; 35 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/15651.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15651/head:pull/15651

PR: https://git.openjdk.org/jdk/pull/15651