[siso] Precise input verification for dawn generators

To enable safe and correct remote execution (Siso/RBE) for Dawn's
code generators, this CL implements a robust self-verification
system that asserts GN inputs match actual Python dependencies.

Key improvements:
1. Strict Assertion System:
   `generator_lib.py` now accepts `--expected-inputs-file` and
   asserts that the actual dependencies (including imported Python
   modules and templates) match the GN-specified inputs exactly.

2. Glob Pattern Support:
   To handle dynamic dependencies like third-party libraries (Jinja2,
   MarkupSafe) and Git metadata (.git/HEAD), we introduced glob pattern
   matching in the expected inputs (e.g. `*third_party/jinja2/*`).
   The generator uses `fnmatch` to strictly detect missing inputs
   while safely allowing unused, over-specified inputs. Misplaced
   glob patterns are filtered out from Ninja's physical inputs in
   `generator_lib.gni`.

3. Dynamic Argument Construction:
   The `dawn_json_generator` template in `dawn_generator.gni` now
   automatically detects the presence of optional files (like
   `dawn_wire.json` or `dawn_kotlin.json`) in the target's `inputs` using
   `filter_include`, and dynamically appends the corresponding generator
   arguments (e.g., `--wire-json`). This completely eliminates the need to
   hardcode target-to-JSON mappings in both Python and GN sides.

4. Explicit Target inputs:
   All individual generator targets in `BUILD.gn` files now explicitly
   list their required templates and JSON files in their `inputs`,
   ensuring clean and maintainable dependency tracking.

Bug: 466134210
Change-Id: I0155aa259474c8e8b8e8e08861c55fd1fed63c04
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/315915
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>