DeployInst memory leak

[gonuke]

There appears to be a memory leak in DeployInst at this location.

A clone of a prototype is added to the context at this line, ultimately invoking a new under the hood. This clone is only registered with the prototype list under certain conditions and is not deleted in the cases where it is not registered and no longer needed.

This may be related to failures witnessed by @jbae11 and others.