RFR: JDK-8275688: Suppress warnings on non-serializable non-transient instance fields in DualPivotQuicksort

[Joe Darcy]

This should be the last core libraries cleanup of  non-serializable non-transient instance fields ahead of the upcoming javac lint warnings: https://mail.openjdk.java.net/pipermail/jdk-dev/2021-October/006166.html

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Commit messages:
 - JDK-8275688: Suppress warnings on non-serializable non-transient instance fields in DualPivotQuicksort

Changes: https://git.openjdk.java.net/jdk/pull/6058/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6058&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275688
  Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6058.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6058/head:pull/6058

PR: https://git.openjdk.java.net/jdk/pull/6058