* Fast list and weak concurrent bag

* Add fiber dumping and cleanup dumping method variations

* auto-gc

* Add flag so it's possible to turn off root fiber tracking

* Delete dead code

* fix merge compilation error

* Move FastList to shared

* Fix native error

* Improve performance of gc

* Use signal handlers and hash code to trigger fiber dumps

* Add docs and final

* Fix bug in calculating bucket; add wrapper around String for Scala.js

* Don't forget to track new roots created in fork

* Add test for Fiber.roots

* Be more generous in auto GC of weak concurrent bag

* Add randomness to auto gc test

* Slight bump to performance

* Make sure no fibers are lost in the cracks

* Eliminate dead code

* Begone CauseSpec failures!

* enable fiber roots

Co-authored-by: Adam Fraser <adam.fraser@gmail.com>