RFR: 8315999: Improve Date toString performance

[温绍锦]

On Mon, 11 Sep 2023 12:12:17 GMT, 温绍锦 <duke at openjdk.org> wrote:

> improve date toString performance, includes:
> 
> java.util.Date.toString
> java.util.Date.toGMTString
> java.time.Instant.toString
> java.time.LocalDate.toString
> java.time.LocalDateTime.toString
> java.time.LocalTime.toString

@cl4es can you help me to review this PR?

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PR Comment: https://git.openjdk.org/jdk/pull/15658#issuecomment-1713812730