RFR: 8366854: Extend jtreg failure handler with THP info [v2]

[Stefan Karlsson]

> I propose that we also dump /proc/meminfo, /proc/vmstat, and /sys/kernel/mm/transparent_hugepage/{enabled, defrag} from the failure handler.
> 
> This information has been helpful when investigating a failure where there was an unexpected lack of transparent huge pages.

Stefan Karlsson has updated the pull request incrementally with one additional commit since the last revision:

  Add shmem_enabled

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27086/files
  - new: https://git.openjdk.org/jdk/pull/27086/files/0470c67f..d95e72a1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27086&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27086&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27086.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27086/head:pull/27086

PR: https://git.openjdk.org/jdk/pull/27086