This will enable running the tests on Linux.

Bug: angleproject:5530
Change-Id: I7cd2155fac89d395a8bebacb2f1a44be0e7d3739
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2644723Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>