Windows process not killed after stop build

When running a Bamboo plan that starts a Windows process and manually stopping the plan, the build ends; however, the Windows process that is running the build action is left running. Here is a simple way to reproduce:

1. Create a build to run on Windows
2. Add a script task with

   rem ping waits 1 second between pings
   rem this will run for 120 seconds
   
   ping -n 121 127.0.0.1 > nul
   

3. Run the build
   • Notice the PING process running in task manager
4. Stop the build
5. Notice the PING process continues running until the 120 seconds is up - this is the process that should be killed