RFR: JDK-8328930: [AIX] remove pase related coding [v2]

[Matthias Baesken]

> We still have quite a lot of OS400 / pase related coding in the hotspot AIX codebase. But this does not work and was never supported in OpenJDK. So we can remove this.

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  adjust/remove some comments

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18471/files
  - new: https://git.openjdk.org/jdk/pull/18471/files/d1c4c7de..ba02f086

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18471&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18471&range=00-01

  Stats: 10 lines in 1 file changed: 0 ins; 9 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18471.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18471/head:pull/18471

PR: https://git.openjdk.org/jdk/pull/18471