RFR: 8241403: JavaThread::get_thread_name() should be ThreadSMR-aware [v6]

[Daniel D.Daugherty]

> A minor fix to add a new function:
> 
>     bool Thread::is_JavaThread_protected(const JavaThread* p)
> 
> that returns true when the target JavaThread* is protected and false
> otherwise. Update JavaThread::get_thread_name() to create a
> ThreadsListHandle and use the new is_JavaThread_protected(). Also
> update JvmtiTrace::safe_get_thread_name() to use the new
> is_JavaThread_protected().
> 
> This fix is tested via a Mach5 Tier[1-8] run.

Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:

  Address dholmes-ora CR3 comments.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2535/files
  - new: https://git.openjdk.java.net/jdk/pull/2535/files/19fe9538..71aec8c2

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2535&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2535&range=04-05

  Stats: 85 lines in 4 files changed: 31 ins; 33 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2535.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2535/head:pull/2535

PR: https://git.openjdk.java.net/jdk/pull/2535