spirv-fuzz: handle case where maximum id bound is reached

spirv-fuzz will add ids to a module, and could hit the maximum id bound.

Some care will ultimately be required to (a) pack ids, both in transformations and in the module, to avoid reaching the bound, and (b) bail out gracefully in the case where the id bound is truly reached.

Start by tracing spirv-fuzz transformations that add IDs and how the module tracks its maximum ID bound. Define the handling for both ID packing and graceful failure when the bound is reached; the issue provides no specific files or tests, so the relevant code and coverage must first be located.

Written by the indexing model from the issue text.