runtime: decentralize concurrent sweep termination
runtime: decentralize concurrent sweep termination

This moves concurrent sweep termination from the coordinator to the
off->mark transition. This allows it to be performed by all Gs
attempting to start the GC.

Updates #11970.

Change-Id: I24428e8599a759398c2ef7ec996ba755a448f947
Reviewed-on: https://go-review.googlesource.com/16356
Reviewed-by: Rick Hudson <838bd060584c511f21c75c69ea04b7b120d86af0@golang.org>
Run-TryBot: Austin Clements <7ea35d812706d9213868749011af1ed4fa2f6aa0@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

akutz/go,suncycheng/go,binarycrusader/go,roth1002/go,CAFxX/go,josharian/go,Samurais/go,momchil-velikov/go,akutz/go,ImJasonH/go,roth1002/go,derekmarcotte/go,rachtsingh/gogojuice,nawawi/go,linux-on-ibm-z/go,rachtsingh/gogojuice,rachtsingh/gogojuice,sndnvaps/go,akutz/go,polyverse-security/go,Cofyc/go,Samurais/go,ImJasonH/go,linux-on-ibm-z/go,odeke-em/go,cloudflare/go,deft-code/go,ImJasonH/go,ImJasonH/go,codestation/go,linux-on-ibm-z/go,mwhudson/go,fjballest/golang,vanloswang/go,Jordanzuo/go,ImJasonH/go,vanloswang/go,suncycheng/go,josharian/go,Samurais/go,kim-racktop/go,josharian/go,golang/go,derekmarcotte/go,mwhudson/go,akutz/go,derekmarcotte/go,Endika/go,fjballest/golang,cyberroadie/go,binarycrusader/go,odeke-em/go,miolini/go,linux-on-ibm-z/go,momchil-velikov/go,kim-racktop/go,theif519/go,momchil-velikov/go,mwhudson/go,akutz/go,nawawi/go,golang/go,suncycheng/go,theif519/go,goodlang/good,binarycrusader/go,miolini/go,codestation/go,polyverse-security/go,derekmarcotte/go,golang/go,4ad/go,Samurais/go,mwhudson/go,suncycheng/go,odeke-em/go,linux-on-ibm-z/go,ImJasonH/go,miolini/go,odeke-em/go,cloudflare/go,4ad/go,nawawi/go,CAFxX/go,codestation/go,golang/go,Samurais/go,vsekhar/elastic-go,roth1002/go,deft-code/go,deft-code/go,Jordanzuo/go,kim-racktop/go,Endika/go,roth1002/go,derekmarcotte/go,fjballest/golang,Jordanzuo/go,cloudflare/go,cloudflare/go,cyberroadie/go,goodlang/good,kim-racktop/go,goodlang/good,miolini/go,codestation/go,fjballest/golang,cyberroadie/go,kim-racktop/go,CAFxX/go,ganboing/go-esx,golang/go,polyverse-security/go,deft-code/go,mwhudson/go,polyverse-security/go,rachtsingh/gogojuice,Cofyc/go,deft-code/go,polyverse-security/go,ganboing/go-esx,cyberroadie/go,roth1002/go,odeke-em/go,Endika/go,ganboing/go-esx,nawawi/go,miolini/go,odeke-em/go,roth1002/go,akutz/go,4ad/go,Cofyc/go,vsekhar/elastic-go,golang/go,suncycheng/go,deft-code/go,goodlang/good,josharian/go,codestation/go,momchil-velikov/go,Jordanzuo/go,josharian/go,theif519/go,momchil-velikov/go,cyberroadie/go,rachtsingh/gogojuice,polyverse-security/go,sndnvaps/go,roth1002/go,binarycrusader/go,CAFxX/go,derekmarcotte/go,Endika/go,rachtsingh/gogojuice,deft-code/go,suncycheng/go,CAFxX/go,Samurais/go,Endika/go,momchil-velikov/go,Endika/go,josharian/go,vsekhar/elastic-go,deft-code/go,Samurais/go,goodlang/good,vanloswang/go,vsekhar/elastic-go,polyverse-security/go,sndnvaps/go,Jordanzuo/go,vanloswang/go,nawawi/go,ganboing/go-esx,suncycheng/go,vanloswang/go,kim-racktop/go,4ad/go,fjballest/golang,sndnvaps/go,Jordanzuo/go,cyberroadie/go,Jordanzuo/go,binarycrusader/go,odeke-em/go,sndnvaps/go,4ad/go,ImJasonH/go,nawawi/go,golang/go,vsekhar/elastic-go,derekmarcotte/go,vanloswang/go,goodlang/good,vanloswang/go,Cofyc/go,mwhudson/go,rachtsingh/gogojuice,codestation/go,ImJasonH/go,golang/go,cloudflare/go,rachtsingh/gogojuice,ganboing/go-esx,derekmarcotte/go,Cofyc/go,sndnvaps/go,4ad/go,josharian/go,CAFxX/go,Cofyc/go,sndnvaps/go,josharian/go,Samurais/go,Cofyc/go,codestation/go,4ad/go,fjballest/golang,kim-racktop/go,akutz/go,goodlang/good,nawawi/go,mwhudson/go,binarycrusader/go,kim-racktop/go,fjballest/golang,fjballest/golang,theif519/go,vanloswang/go,goodlang/good,cloudflare/go,linux-on-ibm-z/go,binarycrusader/go,4ad/go,codestation/go,mwhudson/go,cyberroadie/go,linux-on-ibm-z/go,miolini/go,momchil-velikov/go,momchil-velikov/go,CAFxX/go,CAFxX/go,miolini/go,cloudflare/go,linux-on-ibm-z/go,theif519/go,suncycheng/go,ganboing/go-esx,christopher-henderson/Go,vsekhar/elastic-go,polyverse-security/go,Endika/go,nawawi/go,ganboing/go-esx,ganboing/go-esx,miolini/go,vsekhar/elastic-go,Endika/go,theif519/go,binarycrusader/go,odeke-em/go,Jordanzuo/go,vsekhar/elastic-go,akutz/go,theif519/go,sndnvaps/go,cloudflare/go,theif519/go,roth1002/go,Cofyc/go,cyberroadie/go