Piotr Tabor 68f2cb8c77 Fix ExampleAuth from integration/clientv3/examples (on OsX)
The code now ensures that each of the test is running in its own directory as opposed to shared os.tempdir.
```
$  (cd tests && env go test -timeout=15m --race go.etcd.io/etcd/tests/v3/integration/clientv3/examples -run ExampleAuth)
2022/04/03 10:24:59 Running tests (examples): ...
2022/04/03 10:24:59 the function can be called only in the test context. Was integration.BeforeTest() called ?
2022/04/03 10:24:59 2022-04-03T10:24:59.462+0200	INFO	m0	LISTEN GRPC	{"member": "m0", "grpcAddr": "localhost:m0", "m.Name": "m0"}
```
2022-04-03 14:16:45 +02:00
..
2022-02-28 13:20:27 +01:00