Compat: Add copy T2T, T2B, B2T tests for textureBindingViewDimesion

[greggman]

textureBindingViewDimesion for 2d and 2d-array are tested as those are defaults but cube was not tested. Add some cases.

Note: This is semi-round about. It assumes that at least some tests are compatible with cubemaps which require width and height to match and depthOrArrayLayers to be 6.

Because of the structure of the tests and the cube requirements not all cases are tested. In particular, compressed cube textures are not tested. depth and stencil are not tested.

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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.