We used not to emit canonical indexes for arrays and structs into
WasmModule::signature_ids, which resulted in signature_ids not referring
to the correct type indices in a WasmModule.

Changes:
- Rename signature_ids to canonical_type_ids.
- Emit trivial canonical type ids for structs and arrays.
- Add a test to catch the existing bug.
- Improve DCHECKs for module type accessors.

Bug: v8:7748
Change-Id: I67ad58865e35b459b21db12557564b652035db75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2444989
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70318}