gulp baseline-accept not working #29297

1. Change some test and run tests. Verify that the baselines change and that files exist in tests/baselines/local/
2. Run gulp baseline-accept

Expected behavior:

Files are moved from local/ to reference/

Actual behavior:
No move. jake baseline-accept produces the expected behaviour.

Here's the output:

✔ baselines  [add-globalThis|✚ 8…1⚑ 1]$ gulp baseline-accept
[12:19:27] Working directory changed to ~/ts
[12:19:28] Using gulpfile ~/ts/Gulpfile.js
[12:19:28] Starting 'baseline-accept'...

I suspect this is a Unix-specific bug since I haven't heard anybody else on the team complaining about it.