[Thread] loose the restriction on the setEnabled API behavior

It's too strict that the device must rejoin the network after being
enabled again. This probably don't work on mobile devices. remove the
CTS case for now.

Change-Id: I3a4511f4b2fddddf982206720bbb61f718bc8327
diff --git a/thread/tests/cts/src/android/net/thread/cts/ThreadNetworkControllerTest.java b/thread/tests/cts/src/android/net/thread/cts/ThreadNetworkControllerTest.java
index ba7392c..ff7d027 100644
--- a/thread/tests/cts/src/android/net/thread/cts/ThreadNetworkControllerTest.java
+++ b/thread/tests/cts/src/android/net/thread/cts/ThreadNetworkControllerTest.java
@@ -749,17 +749,6 @@
     }
 
     @Test
-    public void setEnabled_toggleAfterJoin_joinsThreadNetworkAgain() throws Exception {
-        joinRandomizedDatasetAndWait(mController);
-
-        setEnabledAndWait(mController, false);
-        assertThat(getDeviceRole(mController)).isEqualTo(DEVICE_ROLE_STOPPED);
-        setEnabledAndWait(mController, true);
-
-        runAsShell(ACCESS_NETWORK_STATE, () -> waitForAttachedState(mController));
-    }
-
-    @Test
     public void setEnabled_enableFollowedByDisable_allSucceed() throws Exception {
         joinRandomizedDatasetAndWait(mController);
         CompletableFuture<Void> setFuture1 = new CompletableFuture<>();