This version adds subgroupMinSize/subgroupMaxSize, textureBindingViewDimension, GPUAdapterInfo.isFallbackAdapter, and tweaks some type definitions.

idl_test.ts needed to change because bitmask types changed from object types to interface types, which ran into this subtle difference between the two: microsoft/TypeScript#15300

There shouldn't be any significant test behavior changes but since most of these edits are in common files I wasn't able to verify.

Issue: None

Requirements for PR author:

• [n/a] 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:

• [n/a] Tests are properly located in the test tree.
• [n/a] Test descriptions allow a reader to "read only the test plans and evaluate coverage completeness", and accurately reflect the test code.
• [n/a] 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.