cts: Enforce turning off /dev/mem and /dev/kmem

Android kernels should have CONFIG_DEVMEM and CONFIG_DEVKMEM
not set and ueventd should not have any reason to be creating
these character nodes. selinux will block access if these
nodes exist, we need to check if the nodes got created.

(Cherry pick from commit 976f0108b91b005748e462e4304efd7e4389da2f)

Bug: 19549480
Change-Id: I588cef5f494ff33a45f99721a874ec3c1ef92b3e
diff --git a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
index f590f97..2d8c660 100644
--- a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
+++ b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
@@ -156,6 +156,7 @@
         assertFalse(f.canRead());
         assertFalse(f.canWrite());
         assertFalse(f.canExecute());
+        assertFalse(f.exists());
     }
 
     @MediumTest
@@ -182,6 +183,7 @@
         assertFalse(f.canRead());
         assertFalse(f.canWrite());
         assertFalse(f.canExecute());
+        assertFalse(f.exists());
     }
 
     @MediumTest