RFR: 8378675: PPC64: increase instruction cache line size [v4]

[David Briemann]

> Set the instruction cache line size for Power to 128 bytes.
> 
> Add functions to retrieve the data cache line size and instruction cache line size from the system (AIX & Linux).

David Briemann has updated the pull request incrementally with three additional commits since the last revision:

 - fix calculation
 - revert copyright header updates
 - refactor get cache methods from os into vm_version

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29918/files
  - new: https://git.openjdk.org/jdk/pull/29918/files/dfa4bbf9..24019515

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29918&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29918&range=02-03

  Stats: 119 lines in 10 files changed: 80 ins; 31 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/29918.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29918/head:pull/29918

PR: https://git.openjdk.org/jdk/pull/29918