[jdk11u-dev] RFR: 8273341: Update Siphash to version 1.0

[Zhengyu Gu]

A clean backport for parity with Oracle 11.0.15.

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Commit messages:
 - Backport 6cf4cd1aa46414d9af17f3704b27d0d381a17ee8

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/781/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=781&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273341
  Stats: 22 lines in 2 files changed: 7 ins; 0 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/781.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/781/head:pull/781

PR: https://git.openjdk.java.net/jdk11u-dev/pull/781