Comment publish and CQ try job submission issues

[caitp]

Often, when publishing comments, the initial set of comments will be sent, followed by a second empty comment immediately afterwards.

Similarly, occasionally, adding try jobs via the web interface will add the same jobs twice! I expect this is somehow related to finicky mouse event handling, and may only affect certain pointer devices (this one being a MacBook Pro (Mid 2015) trackpad). However, regardless of whether the issue is a clientside issue or not, the server should probably have a 60 second timeout between attempts to launch a try job for a specific issue, to prevent this from occurring