[val] Enforce limit to location number for spirv backend

The specific value comes from spirv-val, which rejects shaders with
values out of range.

The specific limit is far beyond what should be seen in the real
world, because the API side (Dawn) will enforce a much lower device
specific limit, thus never attempt to create a shader module with an
out of range value. The limit is primarily for the fuzzers and other
offline scenarios to prevent unexpected backend failures.

Fixes: 509515389
Change-Id: I2e8bdd9439e4ff44757cf4f58db1735e5295d7c9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/306695
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: James Price <jrprice@google.com>
Auto-Submit: Ryan Harrison <rharrison@chromium.org>