Includes two small fixes:

 - add .gitignore for trace tests.
 - fix path for restricted traces, should fix bots.

Bug: angleproject:4386
Change-Id: I51c657c4f2e772411e95faa76188d43c8b6981f7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2057350Reviewed-by: Cody Northrop <cnorthrop@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>