Pull request: imp-tests

Merge in DNS/adguard-home from imp-tests to master

Squashed commit of the following:

commit ea5b4e7a93359ae4800f75e77d02944a4f5d2df8
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Oct 27 15:12:45 2022 +0300

    all: imp tests, use testutil

internal/stats/stats_test.go

@@ -10,7 +10,6 @@ import (
 	"sync/atomic"
 	"testing"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
 	"github.com/AdguardTeam/AdGuardHome/internal/stats"
 	"github.com/AdguardTeam/golibs/testutil"
 	"github.com/stretchr/testify/assert"
@@ -18,7 +17,7 @@ import (
 )
 
 func TestMain(m *testing.M) {
-	aghtest.DiscardLogOutput(m)
+	testutil.DiscardLogOutput(m)
 }
 
 // constUnitID is the UnitIDGenFunc which always return 0.