Add wasm32 support to integration tests

[kevinheavey]

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I'm not sure if all of this crate works on wasm32 but the integration tests work fine with minor changes to the test code:

• Use wasm_bindgen_test when target_arch = "wasm32"
• Replace #[should_panic] with regular assertions in code, because should_panic doesn't work with wasm_bindgen_test
• Replace u32::MAX in one test with usize::MAX

I also added a wasm-test job to CI