Implement ArrayBuffer and ArrayBufferView variants of WebSocket::Send

[jdm]

https://dxr.mozilla.org/servo/source/tests/wpt/web-platform-tests/websockets/binary/004.html fails with:

WebSockets: Send/Receive ArrayBuffer, size greater than network array buffer
----------------------------------------------------------------------------
Expected PASS, got FAIL
assert_equals: expected (number) 100000 but got (undefined) undefined

This corresponds to assert_equals(e.data.byteLength, datasize); in the test, where e.data is supposed to be an ArrayBuffer object. console.log(e.data) shows [object ArrayBuffer], while console.log(e.data.byteLength) shows undefined, and console.log(Object.getPrototypeOf(e.data)) shows the empty string. I am very confused by these results.

[jdm]

I figured it out - all of the arraybuffer tests provide arraybuffers as input, but we haven't implemented that yet so they get converted to strings. This means that the tests all send input which is the stringified arraybuffer object, so they receive a string like [object ArrayBuffer] instead of binary data that gets converted into an arraybuffer object.

[jdm]

This needs to wait until #5014, unfortunately. I don't think we can handle overloads of webidl methods that include object types.

[Ms2ger]

We probably could, but would need to handle interface types manually... Not sure if the distinction would be detectable.

[jdm]

Duplicate of #20347.