RFR: 8330846: Add stacks of mounted virtual threads to the HotSpot thread dump [v12]

[Inigo Mediavilla Saiz]

> Print the stack traces of mounted virtual threads when calling `jcmd <pid> Thread.print`.

Inigo Mediavilla Saiz 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 15 additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into txominpelu_8330846_add_stack_vthreads
 - Include virtual thread name in output
 - Incorporate @tstuefe's remarks
 - Remove dead code
 - Remove extra indentation (leave it for the next PR)
 - Cleanup test
   
   - Stop virtualthread
   - Remove unneeded imports
   - Remove modules that are not needed
 - Fix copyright year
 - Print mounted virtual thread after carrier
 - Add indentation for virtual thread stack
 - Update test/hotspot/jtreg/serviceability/dcmd/thread/PrintVirtualThreadTest.java
   
   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>
 - ... and 5 more: https://git.openjdk.org/jdk/compare/ab51e287...ba3385a4

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19482/files
  - new: https://git.openjdk.org/jdk/pull/19482/files/a97184c3..ba3385a4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19482&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19482&range=10-11

  Stats: 26276 lines in 507 files changed: 19189 ins; 4947 del; 2140 mod
  Patch: https://git.openjdk.org/jdk/pull/19482.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19482/head:pull/19482

PR: https://git.openjdk.org/jdk/pull/19482