RFR: 8307068: store a JavaThread* in the java.lang.Thread object after the JavaThread* is added to the main ThreadsList

[Daniel D. Daugherty]

A small fix to store a JavaThread* in the java.lang.Thread object after the JavaThread*
is added to the main ThreadsList. Also adds the following:
- `java_lang_Thread::thread_acquire()`
- `java_lang_Thread::release_set_thread()`

And uses them on an as-needed basis.

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Commit messages:
 - Forgot to checkpoint the use of java_lang_Thread::thread_acquire(thread_oop) in ThreadsListHandle::cv_internal_thread_to_JavaThread().
 - dholmes CR - follow the foo_acquire() and release_set_foo() convention;
 - 8307068: store a JavaThread* in the java.lang.Thread object after the JavaThread* is added to the main ThreadsList
 - 8307067: remove broken EnableThreadSMRExtraValidityChecks option

Changes: https://git.openjdk.org/jdk/pull/13723/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13723&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307068
  Stats: 38 lines in 6 files changed: 18 ins; 12 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/13723.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13723/head:pull/13723

PR: https://git.openjdk.org/jdk/pull/13723