Auto merge of #122 - antrik:fix-bench, r=Wafflespeanut
Auto merge of #122 - antrik:fix-bench, r=Wafflespeanut

Fix benchmarks with `OsIpcReceiver` not being `Sync` anymore

The first commit is the minimal fix to get it working again.

The second patch switches to a different thread handling approach, which inexplicably produces lower overhead in some (unrelated) cases on my system...

servo/ipc-channel