Remove bogus unused import to fix FTBFS with python3.12

--- src/mojo/public/tools/mojom/mojom/fileutil.py.old	2023-06-21 20:56:20.422273900 +0200
+++ src/mojo/public/tools/mojom/mojom/fileutil.py	2023-07-14 15:40:21.994145300 +0200
@@ -3,7 +3,6 @@
 # found in the LICENSE file.
 
 import errno
-import imp
 import os.path
 import sys
 
--- src/mojo/public/tools/mojom/mojom/parse/lexer.py.old	2023-06-21 20:56:20.430277900 +0200
+++ src/mojo/public/tools/mojom/mojom/parse/lexer.py	2023-07-14 19:34:30.806158300 +0200
@@ -2,7 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import imp
 import os.path
 import sys