Fix telemetry test flakiness

In telemetry test we are using an external service for checking
status codes and that service can have intermittent outages which
cause this test to fail. Retrying the request should make the
test a bit more reliable.

test/src/telemetry/test_telemetry.c

@@ -23,6 +23,12 @@
 #define HTTPS_PORT 443
 #define TEST_ENDPOINT "postman-echo.com"
 
+/* Since we rely on an external service to test request statuses, we should retry
+ * a few times if we are not getting the correct response. This should reduce
+ * test flakiness.
+ */
+#define INVALID_STATUS_RETRIES 5
+
 TS_FUNCTION_INFO_V1(ts_test_status);
 TS_FUNCTION_INFO_V1(ts_test_status_ssl);
 TS_FUNCTION_INFO_V1(ts_test_status_mock);
@@ -76,17 +82,33 @@ test_factory(ConnectionType type, int status, char *host, int port)
 		ts_connection_mock_set_recv_buf(conn, test_string, strlen(test_string));
 #endif
 
-	req = build_request(status);
+	int retries = 0;
+	while (retries < INVALID_STATUS_RETRIES)
+	{
+		req = build_request(status);
 
-	rsp = ts_http_response_state_create();
+		rsp = ts_http_response_state_create();
 
-	err = ts_http_send_and_recv(conn, req, rsp);
+		err = ts_http_send_and_recv(conn, req, rsp);
 
-	ts_http_request_destroy(req);
-	ts_connection_destroy(conn);
+		ts_http_request_destroy(req);
 
-	if (err != HTTP_ERROR_NONE)
-		elog(ERROR, "%s", ts_http_strerror(err));
+		if (err != HTTP_ERROR_NONE)
+			elog(ERROR, "%s", ts_http_strerror(err));
+
+		/* We are mocking the connection, no need to retry */
+		if (type == CONNECTION_MOCK)
+			break;
+
+		/* Got what we want, no need to retry */
+		if (ts_http_response_state_valid_status(rsp) ||
+			ts_http_response_state_status_code(rsp) == status)
+			break;
+
+		retries++;
+	}
+
+	ts_connection_destroy(conn);
 
 	if (!ts_http_response_state_valid_status(rsp))
 		elog(ERROR,