<i18n dev> RFR: 8337279: Optimize format instant [v15]

[Shaojin Wen]

> By removing the redundant code logic in DateTimeFormatterBuilder$InstantPrinterParser#formatTo, the codeSize can be reduced and the performance can be improved.

Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:

  from @natoj

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20353/files
  - new: https://git.openjdk.org/jdk/pull/20353/files/5924935e..5ca4d6e9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20353&range=14
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20353&range=13-14

  Stats: 4 lines in 2 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20353.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20353/head:pull/20353

PR: https://git.openjdk.org/jdk/pull/20353