RFR: 8330049: Remove unused AbstractLinker::linkerByteOrder [v2]

[Jorn Vernee]

> Please review this simple cleanup which removes the `AbstractLinker::linkerByteOrder` method. It was only used in `AixPPC64Linker`, where we know it will always return `ByteOrder.BIG_ENDIAN` so we can just replace the call with that.
> 
> Testing: Local run of `run-test-jdk_foreign`.

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  update copyright years

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18726/files
  - new: https://git.openjdk.org/jdk/pull/18726/files/12ccb842..eff6f471

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18726&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18726&range=00-01

  Stats: 10 lines in 10 files changed: 0 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/18726.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18726/head:pull/18726

PR: https://git.openjdk.org/jdk/pull/18726