[Bug] Buffer doesn't support usc-2, but Buffer.isEncoding supports that?!

[ghost]

Nodejs：10.7.0
OS：Win 8.1 (SP1, x32)

If you use Buffer.isEncoding('usc-2'), this will return you true.

However, most of Buffer methods are NOT supporting this encoding. A typical example is (either of them will throw exceptions)：

const c = new Buffer('aaa','usc-2');
const c = Buffer.from('aaa','usc-2');

Is there anything conflicting with the encoding type?

[ghost]

@nodejs/buffer

[devsnek]

what is usc-2? is that a misspelling of UCS-2?

[ghost]

@devsnek：Not sure why we have this encoding？

Now check this following in 10.7.0：

And should I help you to remove that in internal\util's normalizeEncoding?

Waiting for your response :)

[devsnek]

it was introduced in 341770f by @BridgeAR

[ghost]

@mscdex ：thanks anyway!
I've also removed benchmark tests for usc-2.

[Trott]

/ping @addaleax @joyeecheung