A packed artifact zip is not cleaned up on windows

Issue Summary

This is reproducible on Data Center: yes

Steps to Reproduce

1. Enable "Package threshold" for the remote artifact handler, and set the threshold to 2
2. Create a plan that will create an artifact consisting of >2 files (so the artifact will be packed into a single file)
3. Run the plan (on any agent)
4. Create another plan that will download the artifact
5. Run this new plan on a Windows agent

Expected Results

The temporary artifact archive zip (created in C:\Users\<agent_user>\AppData\Local\Temp) is cleaned up 

Actual Results

The temporary artifact archive zip is not cleaned up. Removing the file manually requires agent restart (otherwise it will fail with "file is being used by another process.")

Workaround

Disable package threshold. Note that this may lead to much higher disk utilization because artifacts won't be packaged