We can now run unit tests with the fuzz feature on, and they'll pass,
which is some assurance that fuzzing with the feature on won't lead to
spurious failures due to the fuzz harness inadequately simulating message
signing.
Instead of repeating ourselves in defining one big test for the wasm
target, we can override the `test` attribute with the `wasm-bindgen-test`
one and therefore automatically run all (supported) tests in wasm.
Unfortunately, wasm doesn't support catching panics yet which means we
have to disable the `test_panic_raw_ctx` test.
Andrew Poelstra
Tobin Harding
Thomas Eizinger
Tibo-lg