Intermittent `cannot remove a vacant resource` panics running in deno

[andyleiserson]

This is reproducible for me (Mac M1) by running cargo xtask cts 'webgpu:api,validation,encoding,cmds,copyTextureToTexture:texture_format_compatibility:*'. It doesn't always panic at the same place. Without the #7391 fixes, the tests fail, but this problem is reproducible either with or without the error reporting changes.

I was not able to reproduce in Firefox, so I've tentatively marked this as a deno issue, although given the nature of the problem, that may or may not be accurate.

[ErichDonGubler]

For Firefox, errors of this sort happen when it forgets to register or free up an ID, and either an ID that wgpu-core isn't aware of gets used, or we try to use an ID that's not in a state (in wgpu-core) that the user agents expects.

I agree that this is likely a Deno-specific issue.