RFR: 8325186: JVMTI VirtualThreadGetThreadStateClosure class is no longer used and should be removed [v2]

[Koichi Sakata]

> This pull request removes an unused class. 
> 
> I have investigated when this class was no longer in use. In the initial push of the virtual thread code (21972f45a64741ec3002499ef532e363cc3e9f93), there was only the definition of this class. I also checked subsequent commits, and it has never been used since the push.

Koichi Sakata has updated the pull request incrementally with one additional commit since the last revision:

  Update copyright year

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18341/files
  - new: https://git.openjdk.org/jdk/pull/18341/files/09af50a0..b37187ee

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18341&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18341&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18341.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18341/head:pull/18341

PR: https://git.openjdk.org/jdk/pull/18341