Bug in ws client mock - wrong close code when server not found

[easy-death]

Current native Websocket implementation returns wasClean: false and code: 1006 when wrong url is provided.

mock-socket/src/websocket.js

Line 94 in eab4bf5

this.dispatchEvent(createCloseEvent({ type: 'close', target: this, code: CLOSE_CODES.CLOSE_NORMAL }));

[easy-death]

@Atrue could you please check, tests passing