Fixes the tests not running directly from the VS UI.

BUG=angleproject:1051

Change-Id: Ia299d8e7ad676330902725c114e8f5766db49d82
Reviewed-on: https://chromium-review.googlesource.com/283158Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>