Remove thread dump from support zip

What is the problem

Jira support zip includes three thread dump but they are not particularly useful due to the following reasons.

• Lack of time accuracy - thread dump is a moment in time snapshot of threads activity. To be useful, it must be captured precisely at the time of a problem or otherwise it can be misleading. The current implementation doesn't allow enough timing precision for troubleshooting a problem
• Lack quantity control - The quantity of the thread dump must be proportionate to the problem behavior. e.g., troubleshooting 15 second slowdown would require 5 thread dump taken with 2 second interval to give a clear picture of what happened during the 15 second slowdown. 

Impact of this problem

Administrator often think the thread dump included in the support zip are valid and rely on that to troubleshoot performance problem. This makes the Support team had to explain the difference between the thread dump captured by the support zip, and the manual thread dump generation 

What to improve

From the support standpoint, there is very little upside from having the current thread dump implementation, and it's probably raised more questions than answer.

Ideally we should improve the tool to address the above gaps, or otherwise remove it from the support zip (and rely on native thread dump tooling which is more accurate)