Auto merge of #52349 - RalfJung:once, r=alexcrichton
Auto merge of #52349 - RalfJung:once, r=alexcrichton

sync::Once use release-acquire access modes

Nothing here makes a case distinction like "this happened before OR after that". All we need is to get happens-before edges whenever we see that the state/signal has been changed. Release-acquire is good enough for that.

GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust