grpc-node linux tests are consistently failing on master

https://source.cloud.google.com/results/invocations/e2b2536c-60f2-4757-9170-bb7aff916805/targets

First failure on Jan 18, 100% runs failing since then https://source.cloud.google.com/results/invocations/db5863a8-a057-4dd4-820f-7a7a116b192b/targets