Actually remove the file even if the tests failed

Following review, see https://github.com/PyCQA/pylint/pull/4004\#discussion_r550774984

Author: Pierre-Sassoulas

tests/test_func.py

@@ -168,6 +168,8 @@ def __test_functionality(module_file, messages_file, dependencies):
     if len(sys.argv) > 1:
         FILTER_RGX = sys.argv[1]
         del sys.argv[1]
-    pytest.main(sys.argv)
-    if UPDATE_FILE.exists():
-        UPDATE_FILE.unlink()
+    try:
+        pytest.main(sys.argv)
+    finally:
+        if UPDATE_FILE.exists():
+            UPDATE_FILE.unlink()

tests/test_functional.py

@@ -109,6 +109,8 @@ def test_functional(test_file, recwarn):
     if UPDATE_OPTION in sys.argv:
         UPDATE_FILE.touch()
         sys.argv.remove(UPDATE_OPTION)
-    pytest.main(sys.argv)
-    if UPDATE_FILE.exists():
-        UPDATE_FILE.unlink()
+    try:
+        pytest.main(sys.argv)
+    finally:
+        if UPDATE_FILE.exists():
+            UPDATE_FILE.unlink()