The level parameter needs to be zero for a number of texture overloads.
Bodging the template to emit 0 instead of 1 for any `level : i32` parameter is the easiest fix here.
Change-Id: I69222578efcd0d4f4f267fb59fec691b52786d9c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/57301
Auto-Submit: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Ben Clayton <bclayton@google.com>