<i18n dev> RFR: 8358880: Performance of parsing with DecimalFormat can be improved [v3]

[Johannes Graham]

> This PR replaces construction of intermediate strings to be parsed with more direct manipulation of numbers. It also has a more streamlined mechanism of handling `Long.MIN_VALUE` when parsing longs by using `Long.parseUnsignedLong`
> 
> As a small side-effect it also eliminates the use of a cached StringBuilder in DigitList.
> 
> Testing:
> - GHA
> - Local run of tier 2 and jtreg:jdk/java/text
> - New benchmark: DecimalFormatParseBench

Johannes Graham has updated the pull request incrementally with one additional commit since the last revision:

  Address review comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25644/files
  - new: https://git.openjdk.org/jdk/pull/25644/files/da9e4aea..6953dcfc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25644&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25644&range=01-02

  Stats: 8 lines in 4 files changed: 0 ins; 2 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/25644.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25644/head:pull/25644

PR: https://git.openjdk.org/jdk/pull/25644