RFR: 8304074: [JMX] Add an approximation of total bytes allocated on the Java heap by the JVM [v25]

[Paul Hohensee]

> Please review this addition to com.sun.management.ThreadMXBean that returns the total number of bytes allocated on the Java heap since JVM launch by both terminated and live threads.
> 
> Because this PR adds a new interface method, I've updated the JMM_VERSION to 4, but would be happy to update it to 3_1 instead.

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 95 additional commits since the last revision:

 - Merge master
 - 8304074: Change UnsupportedOperationException in javadoc comment to {@code UnsupportedOperationException}
 - 8306507: [linux] Print number of memory mappings in error reports
   
   Reviewed-by: adinn, sgehwolf
 - 8300086: Replace NULL with nullptr in share/c1/
   
   Reviewed-by: thartmann, chagedorn
 - 8308465: Reduce memory accesses in AArch64 MD5 intrinsic
   
   Reviewed-by: aph, phh
 - 8302218: CHeapBitMap::free frees with incorrect size
   
   Reviewed-by: aboldtch, iklam, tschatzl
 - 8308388: Update description of SourceVersion.RELEASE_21
   
   Reviewed-by: iris
 - 8307190: Refactor ref_at methods in Constant Pool
   
   Reviewed-by: coleenp, iklam
 - 8308458: Windows build failure with disassembler.cpp(792): warning C4267: '=': conversion from 'size_t' to 'int'
   
   Reviewed-by: jiefu
 - 8308034: Some CDS tests need to use @requires vm.flagless
   
   Reviewed-by: iklam
 - ... and 85 more: https://git.openjdk.org/jdk/compare/20185d2c...7b90091b

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13814/files
  - new: https://git.openjdk.org/jdk/pull/13814/files/638756de..7b90091b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13814&range=24
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13814&range=23-24

  Stats: 10880 lines in 222 files changed: 7954 ins; 1723 del; 1203 mod
  Patch: https://git.openjdk.org/jdk/pull/13814.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13814/head:pull/13814

PR: https://git.openjdk.org/jdk/pull/13814