RFR: 8304691: Remove jlink --post-process-path option

[Ian Graves]

Removing the hidden `jlink --post-process-path` option.

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Commit messages:
 - Removing Post Processing functionality

Changes: https://git.openjdk.org/jdk/pull/13126/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13126&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304691
  Stats: 193 lines in 8 files changed: 0 ins; 193 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13126.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13126/head:pull/13126

PR: https://git.openjdk.org/jdk/pull/13126