We shouldn't need to query function pointers now that we're using
a custom loader.

Bug: angleproject:4729
Change-Id: I50f50545a2f29e16ab675afe0155700332c8f670
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2241618Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>