76248a68b2
Running all vmtests in tstest/natlab/vmtest locally was breaking later
tasks in the queue. The goroutine dump on timeout had goroutines hanging
around for 9 minutes, meaning that something was not getting cleaned up.
goroutine 262 [select, 9 minutes]:
gvisor.dev/gvisor/pkg/tcpip/adapters/gonet.commonRead({...})
Add a timeout of Now() to gonet TCP connections when the test ends
(inspired by ServeUnixConn()), and wait for them to shut down before
exiting the test.
Updates #13038
Signed-off-by: Claus Lensbøl <claus@tailscale.com>