Skip flaky tests for linkerd#613 (linkerd#614)

The metrics endpoint tests are flaky because there are no guarantees
that the metrics pipeline has processed events before the metrics
endpoint is read. This can cause CI to fail spuriously.

Disable these tests from running in CI until linkerd#613 is resolved.

proxy/tests/telemetry.rs

@@ -266,7 +266,9 @@ macro_rules! assert_contains {
     }
 }
 
+// https://github.com/runconduit/conduit/issues/613
 #[test]
+#[cfg_attr(not(feature = "flaky_tests"), ignore)]
 fn metrics_endpoint_inbound_request_count() {
     let _ = env_logger::try_init();
 
@@ -295,7 +297,9 @@ fn metrics_endpoint_inbound_request_count() {
 
 }
 
+// https://github.com/runconduit/conduit/issues/613
 #[test]
+#[cfg_attr(not(feature = "flaky_tests"), ignore)]
 fn metrics_endpoint_outbound_request_count() {
     let _ = env_logger::try_init();
 
@@ -502,7 +506,9 @@ fn metrics_endpoint_outbound_response_latency() {
         "response_latency_ms_count{authority=\"tele.test.svc.cluster.local\",direction=\"outbound\",status_code=\"200\"} 4");
 }
 
+// https://github.com/runconduit/conduit/issues/613
 #[test]
+#[cfg_attr(not(feature = "flaky_tests"), ignore)]
 fn metrics_endpoint_inbound_request_duration() {
     let _ = env_logger::try_init();
 
@@ -537,7 +543,9 @@ fn metrics_endpoint_inbound_request_duration() {
         "request_duration_ms_count{authority=\"tele.test.svc.cluster.local\",direction=\"inbound\"} 2");
 }
 
+// https://github.com/runconduit/conduit/issues/613
 #[test]
+#[cfg_attr(not(feature = "flaky_tests"), ignore)]
 fn metrics_endpoint_outbound_request_duration() {
     let _ = env_logger::try_init();