RFR: 8355391: Use Long::hashCode in java.time

[Shaojin Wen]

On Wed, 30 Apr 2025 15:01:08 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Replace manual bitwise operations in `hashCode` implementations of `java.time` with `Long::hashCode`.
>
> lgtm

> @RogerRiggs, @minborg, @naotoj, thanks for the reviews. I've attached successful `tier1,2` results to the ticket. I'd appreciate it if one of you would be kind enough to also sponsor the changes.
> 
> @wenshao, thanks for the tip. I will explore if we can perform similar simplifications in `java.util` too.

I submitted PR #24971 to use Double.hashCode to do similar simplification. 

In addition, sun.nio.ch.FileKey/sun.nio.fs.UnixFileKey/sun.nio.fs.UnixFileStore in java.base can also be simplified similarly.

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PR Comment: https://git.openjdk.org/jdk/pull/24959#issuecomment-2843751482