RFR: 8337716: ByteBuffer hashCode implementations are inconsistent [v2]

[Brian Burkhalter]

> Revert the changes made in #16992 and add some test coverage.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8337716: Statically import StandardOpenOption; rem remove spurious line break

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20451/files
  - new: https://git.openjdk.org/jdk/pull/20451/files/c257988f..ba25d550

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20451&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20451&range=00-01

  Stats: 6 lines in 1 file changed: 1 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20451.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20451/head:pull/20451

PR: https://git.openjdk.org/jdk/pull/20451