Ensure IRC update failure still lets TRC update + bug fix + UTs

[alsanmsft]

Problem/Overview:

In the case where both IRC and traditional run command (TRC) exist on a VM, and there is an update available, both IRC and TRC will update. Previously, if IRC failed to update, then TRC.Update() would error out before copying over the mrseq files, and thus causing a re-trigger of RC to run.

Additionally, in this case, IRC was failing to update if the extension was the test extension, as opposed to the prod extension.

This PR includes:

• RC copies over mrseq files before calling IRC to update
• versionutil.ExtractFromServiceDefinition() now supports the test extension handler name
• UTs to verify changes