Fix texture tests

[greggman]

• webgpu:api,operation,command_buffer,image_copy:rowsPerImage_and_bytesPerRow
• webgpu:api,validation,createTexture:texture_size,3d_texture,compressed_format
• webgpu:api,validation,image_copy,layout_related:required_bytes_in_copy

They all had issues related to the maximum size they were allowed to test and/or the valid max dimension of a compressed texture.

Added getMaxValidTextureSizeForFormatAndDimension which returns the maxiumum valid size for the given format and dimension. In other words it will be the device limit rounded down by block size where appropriate.

• texture_size,3d_texture,compressed_format tests fail for ASTC formats #4380
• required_bytes_in_copy tests fail for ASTC formats with 3D dimension #4381
• rowsPerImage_and_bytesPerRow tests fail for ASTC formats with 3D dimension #4382

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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.

[greggman]

tested on a local build with 'texture-compression-astc-sliced-3d' enabled

[beaufortfrancois]

I've tried those locally as well and it works great! Thank you very much for unblocking https://chromium-review.googlesource.com/c/chromium/src/+/6470184