still pretty much work in progress.
* Introduced init_thread_debug_info() which is used instead of
clear_thread_debug_info() when the thread is created. The latter
requires former initialization.
* user_debug_thread_deleted() is now already invoked in thread_exit(),
not in the undertaker.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27531 a95241bf-73f2-0310-859d-f6bbb57e9c96
cbcebd3330