LWG3343 Ordering of calls to unlock() and notify_all() in Effects element of notify_all_at_thread_exit() should be reversed

[jwakely]

https://cplusplus.github.io/LWG/issue3343

SG1 looked at this in Kona and approved the proposed resolution. LWG should schedule it to poll.

[bstamour]

Poll: accept the proposed resolution of LWG3343 and move to immediate?
|F|A|N|
|12|0|0|