Automatic merge from submit-queue (batch tested with PRs 46429, 46308, 46395, 45867, 45492)
Bump Go version to 1.8.3
This PR also removed this patched version of Go 1.8.1 which we used to use to workaround performance problem of Go 1.8.1.
Fix https://github.com/kubernetes/kubernetes/issues/45216
Ref #46391
@timothysc @bradfitz