The buildbot now uses device_testdex as modes.

Forgot this file in last CL.

Test: run-libcore-tests.sh
Change-Id: I5f62745b88a049c6124342381d02f42d65b737fa
diff --git a/tools/libcore_network_failures.txt b/tools/libcore_network_failures.txt
index e7e31db..380f56b 100644
--- a/tools/libcore_network_failures.txt
+++ b/tools/libcore_network_failures.txt
@@ -8,7 +8,7 @@
   description: "Ignore failure of network-related tests on new devices running Android O",
   result: EXEC_FAILED,
   bug: 74725685,
-  modes: [device],
+  modes: [device_testdex],
   names: ["libcore.libcore.io.OsTest#test_byteBufferPositions_sendto_recvfrom_af_inet",
           "libcore.libcore.net.NetworkSecurityPolicyTest#testCleartextTrafficPolicyWithFtpURLConnection",
           "libcore.libcore.net.NetworkSecurityPolicyTest#testCleartextTrafficPolicyWithHttpURLConnection",