RFR: 8289091: move oop safety check from SharedRuntime::get_java_tid() to JavaThread::threadObj()

[Daniel D. Daugherty]

A trivial move of the oop safety check from SharedRuntime::get_java_tid() to
JavaThread::threadObj(). Also made adjustments to the threadObj() calls in
JavaThread::print_on_error() and JavaThread::get_thread_name_string() so
that we don't get secondary crashes when a JavaThread crashes after it has
detached the GC barrier.

Tested with Mach5 Tier[1-7]. A Mach5 Tier8 will be started this weekend.

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Commit messages:
 - 8289091.cr0

Changes: https://git.openjdk.org/jdk19/pull/69/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk19&pr=69&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289091
  Stats: 28 lines in 2 files changed: 11 ins; 5 del; 12 mod
  Patch: https://git.openjdk.org/jdk19/pull/69.diff
  Fetch: git fetch https://git.openjdk.org/jdk19 pull/69/head:pull/69

PR: https://git.openjdk.org/jdk19/pull/69