* Fix page-migration background thread on fork
After falling off main in the forked child, all the children
try to join on on the parent's monitoring thread. This results
in a deadlock. Parent is waiting for the child to exit, but
the child is trying to join the parent's thread which is
signaled from the parent's static destructors.
Even with just one parent and child, due to copy-on-write
semantics, a child signalling the background thread to join
will still block (thread's updated state is not visible
in the child).
This fix creates background treads on fork per-child with a
pthread_atfork handler, ensuring that each child has its own
monitoring thread.
* Formatting fixes
* Detach page-migration background thread and update test timeout
* Attach files with ctest
* Update corr-id assert
* Tweak on-fork, simplify background thread
* Revert thread detach
Kuricheti, Mythreya
e7d45624d0