[jdk11u-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 11u. 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 11u. Per current policy, there is no update to JMM_VERSION in jmm.h and the new method is marked
> 
> @since 11.0.23

Paul Hohensee has updated the pull request incrementally with one additional commit since the last revision:

  8304074: Switch to @since 11.0.23

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Changes:
  - all: https://git.openjdk.org/jdk11u-dev/pull/2286/files
  - new: https://git.openjdk.org/jdk11u-dev/pull/2286/files/a96d3705..cdf93cb4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2286&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2286&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2286.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2286/head:pull/2286

PR: https://git.openjdk.org/jdk11u-dev/pull/2286