arrayLength() will take a pointer to a storage buffer array.
This pointer may pass through function scoped let statements.
To make this intrinsic easier to generate, inline the pointer lets and
remove chains of &*&*.
Bug: tint:806
Change-Id: Ib2c79a9c38cba7391cbb4313986af9a72b0f0435
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/54060
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@chromium.org>