Auto merge of #22465 - Coder206:userscripts, r=avadacatavra

Update userscripts Option

<!-- Please describe your changes on the following line: -->
userscripts is now formatted as `userscripts=`

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
No success for building `mozjs` on Ubuntu 16.04 system
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #22462 (GitHub issue number if applicable)

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___
Not sure, I plan to run `./mach test-perf`
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22465)
<!-- Reviewable:end -->

etc/ci/performance/runner.py

@@ -75,7 +75,7 @@ def run_servo_test(testcase, url, date, timeout, is_async):
     ua_script_path = "{}/user-agent-js".format(os.getcwd())
     command = [
         "../../../target/release/servo", url,
-        "--userscripts", ua_script_path,
+        "--userscripts=" + ua_script_path,
         "--headless",
         "-x", "-o", "output.png"
     ]