Test Buffer to Buffer and Buffer to/from Image Copies with Problematic Usages

[cwfitzgerald]

WebGL has numerous issues with Index buffers being funky to use correctly, which necessitates various workarounds and nuance in the code dealing with copies. This is exemplified by #3157 but there is additional nuance.

https://github.com/gfx-rs/wgpu/blob/master/wgpu-hal/src/gles/queue.rs#L268-338 is the link to the buffer-to-buffer implementation.

Getting this working is also predicated on having our tests run in the browser.

[dv29]

Is this still valid? i'd like to take a stab at it. I'm new to rust though.

[teoxoy]

I think so; thanks for looking into it!

[dv29]

I'm working on this, its very new to me so i'm going through learn-wgpu but i'm getting stuck with errors. Just wanted to update