tests: apply a couple suggested changes from review.

Signed-off-by: Jiayin Mao <jiayin.mao@datadoghq.com>

tests/e2e/runtime_reconfiguration_test.go

@@ -24,7 +24,6 @@ import (
 
 	"github.com/stretchr/testify/require"
 	"go.etcd.io/etcd/server/v3/etcdserver"
-
 	"go.etcd.io/etcd/tests/v3/framework/e2e"
 )
 
@@ -179,11 +178,14 @@ func addMemberAsLearnerAndPromote(ctx context.Context, t *testing.T, epc *e2e.Et
 	id, err := epc.StartNewProc(ctx, nil, t, true /* addAsLearner */)
 	require.NoError(t, err)
 	_, err = epc.Etcdctl(e2e.WithEndpoints(endpoints)).MemberPromote(ctx, id)
-	attempt := 1
-	for err != nil && (attempt < 4) && strings.Contains(err.Error(), "can only promote a learner member which is in sync with leader") {
-		t.Logf("Learner is not ready yet, retry for the %v time", attempt)
-		time.Sleep(100 * time.Duration(attempt) * time.Millisecond)
+
+	attempt := 0
+	for attempt < 3 {
 		_, err = epc.Etcdctl(e2e.WithEndpoints(endpoints)).MemberPromote(ctx, id)
+		if err == nil || !strings.Contains(err.Error(), "can only promote a learner member which is in sync with leader") {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
 		attempt++
 	}
 	require.NoError(t, err)