Flaky behavior in unit test

[jessicayuen]

--- FAIL: TestGoldenPath (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x164d819]
goroutine 7 [running]:
testing.tRunner.func1.1(0x171cd40, 0x1f507e0)
	/Users/runner/hostedtoolcache/go/1.14.4/x64/src/testing/testing.go:940 +0x2f5
testing.tRunner.func1(0xc0002ac5a0)
	/Users/runner/hostedtoolcache/go/1.14.4/x64/src/testing/testing.go:943 +0x3f9
panic(0x171cd40, 0x1f507e0)
	/Users/runner/hostedtoolcache/go/1.14.4/x64/src/runtime/panic.go:969 +0x166
github.com/envoyproxy/xds-relay/internal/pkg/util/testutils.AssertCounterValue(0xc0002ac5a0, 0xc00052fd70, 0xc00003cba0, 0x22, 0x1)
	/Users/runner/work/xds-relay/xds-relay/go/src/github.com/envoyproxy/xds-relay/internal/pkg/util/testutils/stats.go:14 +0xa9
github.com/envoyproxy/xds-relay/internal/app/orchestrator.TestGoldenPath(0xc0002ac5a0)
	/Users/runner/work/xds-relay/xds-relay/go/src/github.com/envoyproxy/xds-relay/internal/app/orchestrator/orchestrator_test.go:159 +0x88e
testing.tRunner(0xc0002ac5a0, 0x186ff80)
	/Users/runner/hostedtoolcache/go/1.14.4/x64/src/testing/testing.go:991 +0xdc
created by testing.(*T).Run
	/Users/runner/hostedtoolcache/go/1.14.4/x64/src/testing/testing.go:1042 +0x357
FAIL	github.com/envoyproxy/xds-relay/internal/app/orchestrator	0.223s

Discussion: https://envoyproxy.slack.com/archives/CTULFMN91/p1594079452076500

[jessicayuen]

Still happening, albeit less frequently.