RFR: 8356870: HotSpotDiagnosticMXBean.dumpThreads and jcmd Thread.dump_to_file updates [v3]

[Alan Bateman]

> Updates the thread dump generated by HotSpotDiagnosticMXBean.dumpThreads and jcmd Thread.dump_to_file to include thread state and lock information. Also update the HotSpotDiagnosticMXBean.dumpThreads API description to link to a description of the JSON format dump as that format is intended to be parseable/read by tools.
> 
> This PR is dependent on [pull/25425](https://github.com/openjdk/jdk/pull/25425). As noted in that PR, the changes accumulated in the loom repo, and have been split up to make it easier to review.
> 
> The changes include some re-implementation of ThreadDumper. This is because it used PrintStream and didn't fail if there was an I/O error, e.g. file system full. Furthermore, the indentation to pretty print the json was fragile and hard to maintain so this is changed to use a supporting writer class to do this.
> 
> Test coverage is significantly expanded, including updating the test library that is used by several tests to parse the thread dump.
> 
> Testing: tier1-6

Alan Bateman 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 five additional commits since the last revision:

 - Temp fixed until fixed in pull/25425
 - Sync up from loom repo, includes review comments
 - Merge branch 'pull/25425' into JDK-8356870
 - Merge branch 'pull/25425' into JDK-8356870
 - Initial commit

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25429/files
  - new: https://git.openjdk.org/jdk/pull/25429/files/52bb3de7..04f559fb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25429&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25429&range=01-02

  Stats: 30027 lines in 609 files changed: 20669 ins; 6244 del; 3114 mod
  Patch: https://git.openjdk.org/jdk/pull/25429.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25429/head:pull/25429

PR: https://git.openjdk.org/jdk/pull/25429