Refactor tests to run in many environments

[TonyGiorgio]

I've started this with the GlueDB testing. Write the testing functions once and call it from both wasm32 and non-wasm32.

Although additionally, since we want to move towards mutiny working in a worker as well, we should start running tests in browser workers too.

To do this, we need to create seperate test.rs files, unfortunately.

https://docs.rs/wasm-bindgen-test/latest/src/wasm_bindgen_test/lib.rs.html#38