Require compat mode limits

[greggman]

Issue: #4523

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Requirements for PR author:

• All missing test coverage is tracked with "TODO" or .unimplemented().
• New helpers are /** documented */ and new helper files are found in helper_index.txt.
• Test behaves as expected in a WebGPU implementation. (If not passing, explain above.)
• Test have be tested with compatibility mode validation enabled and behave as expected. (If not passing, explain above.)

Requirements for reviewer sign-off:

• Tests are properly located in the test tree.
• Test descriptions allow a reader to "read only the test plans and evaluate coverage completeness", and accurately reflect the test code.
• Tests provide complete coverage (including validation control cases). Missing coverage MUST be covered by TODOs.
• Helpers and types promote readability and maintainability.

When landing this PR, be sure to make any necessary issue status updates.

[kainino0x]

Same concern as #4521, how many tests does this break until browsers finish implementing the new limits? Looks like it's mostly just the relevant test cases, but I'm not sure about the changes in capability_info.ts. You know better how getDefaultLimits would affect tests.

We could start with the specialized tests (capability_checks/limits), and give other browsers time to fix those first.

[greggman]

I don't think it's going to affect that many tests. There's the specific limits tests. Then, checking calls to getDefaultLimits, there's only webgpu:idl,javascript;limits