Fix delegate Worker Thread Pool creation
Fix delegate Worker Thread Pool creation

This error was introduced while fixing nits in the
previous CL.

The Delegate Pool was not created at all and always
fallback to the Async thread pool instead.

Bug: chromium:1091259
Change-Id: I5036836b5d792372636f21e936a03906eb587f67
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2262573
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Commit-Queue: Etienne Bergeron <72977556adb407c83e4c510020c5fe46488477ad@chromium.org>

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