merge branch 'pr-1661'
merge branch 'pr-1661'

  Ensure container tests do not write on the host

LGTMs: d1134a78e2bf26a0abd6c50d47e304ac27e7ea97@cyphar
Closes #1661

kolyshkin/runc,wking/runc,crosbymichael/runc,kolyshkin/runc,cyphar/runc,xiaochenshen/runc,mikebrow/runc,dqminh/runc,justincormack/runc,dqminh/runc,mYmNeo/runc,opencontainers/runc,sunyuan3/runc,estesp/runc,adrianreber/runc,wking/runc,adrianreber/runc,dqminh/runc,mikebrow/runc,dqminh/runc,mikebrow/runc,adrianreber/runc,sunyuan3/runc,wking/runc,laijs/runc,kolyshkin/runc,stefanberger/runc,stefanberger/runc,opencontainers/runc,laijs/runc,sunyuan3/runc,mheon/runc,rhatdan/runc,estesp/runc,mheon/runc,cyphar/runc,opencontainers/runc,mYmNeo/runc,justincormack/runc,xiaochenshen/runc,cyphar/runc,stefanberger/runc,kolyshkin/runc,rhatdan/runc,crosbymichael/runc,opencontainers/runc,crosbymichael/runc,mheon/runc,rhatdan/runc,xiaochenshen/runc,mYmNeo/runc,justincormack/runc,estesp/runc,rhatdan/runc,laijs/runc