There was a goroutine started to log things upon a test that could be
ended at the time `cmd.Wait()` ends.
To solve the problem, when the sub-test ends, ensure we wait until the
command ends when ending the test
The output of `make test` before the fix shows:
```
=== RUN TestNewUDPLogListener
==================
WARNING: DATA RACE
Read at 0x00c0002a8643 by goroutine 74:
testing.(*common).logDepth()
/usr/local/go/src/testing/testing.go:629 +0x132
testing.(*common).Logf()
/usr/local/go/src/testing/testing.go:614 +0x90
k8s.io/ingress-nginx/internal/ingress/metric/collectors.TestProcessCollector.func1.1()
/go/src/k8s.io/ingress-nginx/internal/ingress/metric/collectors/process_test.go:54 +0x140
Previous write at 0x00c0002a8643 by goroutine 72:
testing.tRunner.func1()
/usr/local/go/src/testing/testing.go:856 +0x33e
testing.tRunner()
/usr/local/go/src/testing/testing.go:869 +0x17f
Goroutine 74 (running) created at:
k8s.io/ingress-nginx/internal/ingress/metric/collectors.TestProcessCollector.func1()
/go/src/k8s.io/ingress-nginx/internal/ingress/metric/collectors/process_test.go:50 +0x218
testing.tRunner()
/usr/local/go/src/testing/testing.go:865 +0x163
Goroutine 72 (finished) created at:
testing.(*T).Run()
/usr/local/go/src/testing/testing.go:916 +0x699
testing.runTests.func1()
/usr/local/go/src/testing/testing.go:1157 +0xa8
testing.tRunner()
/usr/local/go/src/testing/testing.go:865 +0x163
testing.runTests()
/usr/local/go/src/testing/testing.go:1155 +0x523
testing.(*M).Run()
/usr/local/go/src/testing/testing.go:1072 +0x2eb
main.main()
_testmain.go:52 +0x222
==================
--- PASS: TestNewUDPLogListener (0.00s)
```
after the patch:
```
=== RUN TestNewUDPLogListener
--- PASS: TestNewUDPLogListener (0.01s)
```
Change-Id: I8ea246d14f5f80b330be19dd5b8299c6762f6d6b
