Revert "SharedMemory: clear file descriptor when explicitly closed."
Bug: 138422309

This reverts commit 20ab1e34273aa179053f5dc93e70c0191a39e91b.

Reason for revert: crashes documented in b/138422309

Change-Id: Ic9e33fdb24bad2b30f0eb357d6752c1834df41d5
(cherry picked from commit 5966196515ec44190386d9966da3f762859b7b78)
diff --git a/core/java/android/os/SharedMemory.java b/core/java/android/os/SharedMemory.java
index 0540e36..3e2ba3d 100644
--- a/core/java/android/os/SharedMemory.java
+++ b/core/java/android/os/SharedMemory.java
@@ -259,9 +259,6 @@
             mCleaner.clean();
             mCleaner = null;
         }
-
-        // Cleaner.clean doesn't clear the value of the file descriptor.
-        mFileDescriptor.setInt$(-1);
     }
 
     @Override