CTS: Add testConnectivityConstraintExecutes_withMobile to knownfailures

The test is not reliable enough, removing now until refactored

Bug: 21262226
Change-Id: Id1e5688cd4df578c908491f4421f487b715532c6
diff --git a/tests/expectations/knownfailures.txt b/tests/expectations/knownfailures.txt
index 754e38a..07ef7fa 100644
--- a/tests/expectations/knownfailures.txt
+++ b/tests/expectations/knownfailures.txt
@@ -104,6 +104,13 @@
   bug: 18091590
 },
 {
+  description: "Test is too flaky on some devices",
+  names: [
+    "android.jobscheduler.cts.ConnectivityConstraintTest#testConnectivityConstraintExecutes_withMobile"
+  ],
+  bug: 21262226
+},
+{
   description: "these tests require a good test scene, so they fail if run in random conditions",
   names: [
     "android.hardware.camera2.cts.AllocationTest#testBlackWhite",