[jdk17u-dev] RFR: 8277990: NMT: Remove NMT shutdown capability [v2]

[Thomas Stuefe]

> This removes the NMT shutdown machinery from hotspot. For details, please see the associated JBS issue, as well as the companion change https://bugs.openjdk.org/browse/JDK-8277946 and CSR https://bugs.openjdk.org/browse/JDK-8277947.
> 
> This is not a clean backport, but the fixes are very minor:
> 
> - the original patch changes perfmemory_posix.cpp, but this hunk is not needed in JDK17
> - A small fix was needed since the "shutdown" dcmd option in JDK17 had been deprecated out of carefulness, not outright removed: https://github.com/openjdk/jdk17u-dev/commit/5ce36d6c210d265a59548bde2f9e53b73bfa5c6f . 
> 
> Testing:
> I manually ran runtime/NMT and all gtest variants for NMT on linux x64 and x86.
> SAP nightlies are scheduled.

Thomas Stuefe 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 branch 'openjdk:master' into tstuefe-backport-5a036ace
 - Fix remaining mention of shutdown in dcmd
 - 8277990: NMT: Remove NMT shutdown capability
   
   Reviewed-by: stuefe, shade

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/1116/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/1116/files/5ce36d6c..1259e5b9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1116&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1116&range=00-01

  Stats: 15 lines in 2 files changed: 11 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1116.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/1116/head:pull/1116

PR: https://git.openjdk.org/jdk17u-dev/pull/1116