RFR: 8273341: Update Siphash to version 1.0

[Coleen Phillimore]

The SipHash hash function that we use for rehashing had an update to avoid a strict aliasing violation.  We compile with anti-aliasing, so it's not a problem for Hotspot, but the fix is made to keep us consistent.

Tested with tier1-3 and special test cases for original issue.

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Commit messages:
 - 8273341: Update Siphash to version 1.0

Changes: https://git.openjdk.java.net/jdk/pull/6482/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6482&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273341
  Stats: 5 lines in 2 files changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6482.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6482/head:pull/6482

PR: https://git.openjdk.java.net/jdk/pull/6482