Try to list files instead of directory in isolate for gl_cts data.
Try to list files instead of directory in isolate for gl_cts data.

Bug: angleproject:3827
Change-Id: I65ed81886dce185bfc7542c321f43cc9bde6ef92
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1771979
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle