[#16615] dev tools: Fix script compatibility with newer arcanist

Summary:
Newer versions of arc commands require scripted (non-interactive) commands to include end of options
flag.

Test Plan:
Jenkins: skip
manual test

Reviewers: jharveysmith, skarri, odeshmukh

Reviewed By: odeshmukh

Subscribers: devops

Differential Revision: https://phabricator.dev.yugabyte.com/D23986

arcanist_util/check-diff-name.py

@@ -61,6 +61,7 @@
 arc_which_cmd = ['arc', 'which']
 if args.base:
     arc_which_cmd += ['--base', 'git:merge-base(origin/master)']
+arc_which_cmd += ['--']  # end of options marker required
 arc_which_out = check_output(arc_which_cmd, cwd=args.repository).decode('utf-8')
 diff_descs = re.findall('D[0-9]+.*', arc_which_out)
 if diff_descs: