[tools] Use sandbox in callstats script

BUG=chromium:611010
NOTRY=true

Review-Url: https://codereview.chromium.org/1976593002
Cr-Commit-Position: refs/heads/master@{#36211}

tools/callstats.py

@@ -139,7 +139,6 @@ def run_site(site, domain, args, timeout=None):
             "--no-default-browser-check",
             "--disable-translate",
             "--disable-seccomp-sandbox",
-            "--no-sandbox",
             "--js-flags={}".format(js_flags),
             "--no-first-run",
             "--user-data-dir={}".format(user_data_dir),