[jdk8u-dev] RFR: 8284758: [linux] improve print_container_info [v3]

[Jonathan Dowland]

> Low-risk, for Oracle parity. Mostly a clean-up. This will ease the future backporting of [JDK-8287011].
> 
> Doesn't apply clean: needs adjusting for paths and also context, to reflect 8u's lack of the pid controller ([JDK-8266490]).
> 
> [JDK-8287011]: https://bugs.openjdk.org/browse/JDK-8287011 (forthcoming)
> [JDK-8287011]: https://bugs.openjdk.org/browse/JDK-8266490 (not considered)

Jonathan Dowland has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge remote-tracking branch 'remotes/jdk8u-dev/master' into 8284758-8u
 - 8284758: [linux] improve print_container_info
   
   Reviewed-by: sgehwolf
   Backport-of: 6c6d5223dfaae268f968f4292356d4be89adb122
 - 8220658: Improve the readability of container information in the error log
   
   Backport-of: 2c4b9e0778e170a17b04217bee66bb6c4fb18c0c

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

Changes:
  - all: https://git.openjdk.org/jdk8u-dev/pull/724/files
  - new: https://git.openjdk.org/jdk8u-dev/pull/724/files/fdb4a87d..63eb95e0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=724&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=724&range=01-02

  Stats: 65153 lines in 356 files changed: 21742 ins; 12776 del; 30635 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/724.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/724/head:pull/724

PR: https://git.openjdk.org/jdk8u-dev/pull/724