[jdk17u-dev] RFR: 8304074: [JMX] Add an approximation of total bytes allocated on the Java heap by the JVM [v2]

[Paul Hohensee]

> I'd like to backport the definition and implementation of com.sun.management.ThreadMXBean.getTotalThreadAllocatedBytes to 17u. The backport CSR is [JDK-8320375](https://bugs.openjdk.org/browse/JDK-8320375). A follow-up bugfix backport of [JDK-8313081](https://bugs.openjdk.org/browse/JDK-8313081) will be done following this backport. The combined backports have been in production at Amazon for two months with no issues. The backport uses the reserved6 slot in jmm.h in order to preserve binary compatibility with 17u. Per current policy, there is no update to JMM_VERSION in jmm.h and the new method is marked
> 
> @since 17.0.10

Paul Hohensee 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 four additional commits since the last revision:

 - Merge branch 'master' into backport-8304074
 - Merge branch 'master' into backport-8304074
 - Merge branch 'master' into backport-8304074
 - Backport 3eced01f9efe2567a07b63343f8559683a2d0517

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/1971/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/1971/files/5741ea34..22905dd5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1971&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1971&range=00-01

  Stats: 2713 lines in 36 files changed: 1455 ins; 831 del; 427 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1971.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1971/head:pull/1971

PR: https://git.openjdk.org/jdk17u-dev/pull/1971