[jdk17u-dev] RFR: 8317678: Fix up hashCode() for ZipFile.Source.Key

[Roland Mesde]

Backporting JDK-8317678: Fix up hashCode() for ZipFile.Source.Key. Fixes the hashCode() implementation and adds a new benchmark test. Ran GHA Sanity Checks (passed), related zip tests (passed) and the new benchmark test  (executed properly). The merge conflict was due to the missing benchmark test file, which is in this PR.

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Commit messages:
 - Backport 8d9a4b43f4fff30fd217dab2c224e641cb913c18

Changes: https://git.openjdk.org/jdk17u-dev/pull/4169/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4169&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317678
  Stats: 282 lines in 3 files changed: 281 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4169.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4169/head:pull/4169

PR: https://git.openjdk.org/jdk17u-dev/pull/4169