<i18n dev> RFR: 8300818: Reduce complexity of padding with DateTimeFormatter [v4]

[Sergey Tsypanov]

> Currently it's O(n) - we do `n` shifts of bytes within `StringBuilder`. This can be reduced to O(1) improving the code like:
> 
> DateTimeFormatter dtf = new DateTimeFormatterBuilder()
>   .appendLiteral("Date:")
>   .padNext(20, ' ')
>   .append(DateTimeFormatter.ISO_DATE)
>   .toFormatter();
> String text = dtf.format(LocalDateTime.now());

Sergey Tsypanov has updated the pull request incrementally with one additional commit since the last revision:

  8300818: Extract separate benchmark

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12131/files
  - new: https://git.openjdk.org/jdk/pull/12131/files/b40de5a8..198cb6ae

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12131&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12131&range=02-03

  Stats: 96 lines in 2 files changed: 66 ins; 27 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/12131.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/12131/head:pull/12131

PR: https://git.openjdk.org/jdk/pull/12131