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

Bug: 138422309

This reverts commit 20ab1e3427.

Reason for revert: crashes documented in b/138422309

Change-Id: Ic9e33fdb24bad2b30f0eb357d6752c1834df41d5

core/java/android/os/SharedMemory.java

@@ -259,9 +259,6 @@ public final class SharedMemory implements Parcelable, Closeable {
             mCleaner.clean();
             mCleaner = null;
         }
-
-        // Cleaner.clean doesn't clear the value of the file descriptor.
-        mFileDescriptor.setInt$(-1);
     }
 
     @Override