Assert valid when using SPIR-V ids Useful for debugging when an uninitialized id is used in the SPIR-V transformer. Bug: angleproject:4888 Change-Id: If446187a8a27a06f5958d5df5bc00d02e98d20e3 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2713268 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>