fix: resolve lint failures in test/functional/feature_filelock.py

- Fix shebang line (remove backslash escape)
- Remove stray 'EOF < /dev/null' at end of file

Resolves lint validation issues while preserving Bitcoin intent from bitcoin#28946.

Author: pasta

test/functional/feature_filelock.py

@@ -1,4 +1,4 @@
-#\!/usr/bin/env python3
+#!/usr/bin/env python3
 # Copyright (c) 2018-2020 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
@@ -53,4 +53,3 @@ def check_wallet_filelock(descriptors):
 
 if __name__ == '__main__':
     FilelockTest().main()
-EOF < /dev/null