proctor is running in a sandbox and it executes tests. If it is able to
handle timeouts, we will know that a test sandbox is alive and proctor
will send SIGTERM to test processes and collect all logs.
In addition, these changes contains a few things:
* upload runsc logs with other test artifacts.
* increase log level for java tests.
* call Fatalf instead of Errorf when we want to terminate a test.
PiperOrigin-RevId: 437385756
Previously, ICMP destination unreachable datagrams were ignored by TCP
endpoints. This caused connect to hang when an intermediate router
couldn't find a route to the host.
This manifested as a Kokoro error when Docker IPv6 was enabled. The Ruby
image test would try to install the sinatra gem and hang indefinitely
attempting to use an IPv6 address.
Fixes#3079.