RFR: 8260263: Remove PtrQueue::_qset [v2]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this trivial(?) removal of dead code pertaining to and including `PtrQueue::_qset`?
> 
> Testing: local compilation, tier1
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Merge branch 'master' into 8260263-remove-ptrqueue-qset
 - Initial commit

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

Changes: https://git.openjdk.java.net/jdk/pull/2194/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2194&range=01
  Stats: 26 lines in 4 files changed: 2 ins; 23 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2194.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2194/head:pull/2194

PR: https://git.openjdk.java.net/jdk/pull/2194