The programs have a different shader interface, to force rebinding
descriptor sets in the Vulkan backend.

Bug: angleproject:4261
Change-Id: I7a18a441483dfe34bd40b5a30ca34b7fd0dc3219
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1990085
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>