Fix TestClusterJoinAndReconnect on macos (#2110)
Fix TestClusterJoinAndReconnect on macos (#2110)

Signed-off-by: Sylvain Rabot <cd2ddbfaad971978dc9dc611bca495388b8445c3@lectra.com>
GoogleCloudPlatform/alertmanager,GoogleCloudPlatform/alertmanager,prometheus/alertmanager,GoogleCloudPlatform/alertmanager,prometheus/alertmanager,prometheus/alertmanager,prometheus/alertmanager,GoogleCloudPlatform/alertmanager