RFR: 8323794: Remove unused jimage compressor plugin configuration [v2]

[Claes Redestad]

> There's an unused concept of a pluginConfig that is passed into the jlink compress plugins, however we always pass null here and the code seems broken (the pluginConfig wouldn't have been stored properly). This seem to be a left-over from a more generic plugin design that never came to fruition.
> 
> This PR cleans out this code from the plugins and decompressors, while keeping the compressed header format intact for backwards compatibility (and in case we want to revisit this in the future)

Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:

  Named offsets

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17443/files
  - new: https://git.openjdk.org/jdk/pull/17443/files/591047b1..7df80e39

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17443&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17443&range=00-01

  Stats: 14 lines in 1 file changed: 8 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17443.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17443/head:pull/17443

PR: https://git.openjdk.org/jdk/pull/17443