TorConnect error when opening browser tools

Seen in 115 with dev build.

Steps to reproduce

1. Open tor browser.
2. Ctrl+Alt+Shift+I to open browser tools.

Result

In the terminal output get the error:

console.log: "TorConnect: Observed TorLogHasWarnOrErr"
25406> console.error: TorMonitorService: 
25406>   Cannot open a control port connection
25406>   Message: Error: authenticate 392c2a774e6e4c4977304d7825664145 -> 515 Authentication failed: Password did not match HashedControlPassword *or* authentication cookie.
25406>   Stack:
25406>     _handleCommandReply@resource://torbutton/modules/tor-control-port.js:327:19
25406> pushMessage@resource://torbutton/modules/tor-control-port.js:399:19
25406> _startMessagePump@resource://torbutton/modules/tor-control-port.js:284:29

Error will be slightly different after !709 (merged), but I can still reproduce the same Authetication failed error.

Expect

No error.

CC @pierov I'm not sure how critical this error is since I've only been able to reproduce it when opening the browser tools, but it might be worth investigating.