FileSystemPermissionTest: fix bad cherrypick

Cherrypick https://android-review.googlesource.com/148230 had the effect
of applying a patch a second time where it had already been applied
(original patch was https://android-review.googlesource.com/137241).
The second cherrypick was not detected as a conflict, and inappropriately
patched other code.

Revert the second cherrypick.

Bug: 21876946
Bug: 21877279
Bug: 19549480
Change-Id: Ia0d5f8c815d9e7b6a650f03b0310483833f41086
diff --git a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
index 4050f53..04b8554 100644
--- a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
+++ b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
@@ -158,7 +158,6 @@
         assertFalse(f.canRead());
         assertFalse(f.canWrite());
         assertFalse(f.canExecute());
-        assertFalse(f.exists());
     }
 
     @MediumTest
@@ -179,7 +178,6 @@
         assertFalse(f.canRead());
         assertFalse(f.canWrite());
         assertFalse(f.canExecute());
-        assertFalse(f.exists());
     }
 
     @MediumTest