The BuiltinPolyfill transform expects the DirectVariableAccess transform
to run after it, but this regressed as part of
https://dawn-review.googlesource.com/c/dawn/+/122203
Add unit test along with e2e 1926.wgsl test.
Bug: tint:1926
Change-Id: I5107453ce152b12e6f2f36930846e1fffa775708
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/131020
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>