Should close original preview tab when relaunching Chrome

[njx]

Currently, if you hit the Go Live button while Chrome is already open with remote debugging turned off, and you say "yes" to relaunching Chrome, you end up with two preview tabs--the tab that was opened before we recognized that Chrome needed to be launched, and a second tab that actually has the live connection. After Chrome is relaunched, we should look for the old tab in the debugger info JSON and close it before opening the new tab.

UPDATE: you have to have "reopen tabs on startup" turned on in Chrome.

[njx]

QRB reviewed

[njx]

Closing this in favor of #3427.