PR contains:

• fix for claiming & deleting prebuilds with immutable params
• unit test for claiming scenario
• unit test for deletion scenario

The parameter resolver was failing when deleting/claiming prebuilds because a value for a previously-used parameter was provided to the resolver, but since the value was unchanged (it's coming from the preset) it failed in the resolver. The resolver was missing a check to see if the old value != new value; if the values match then there's no mutation of an immutable parameter.