Fix strong->value reference coercion in calls.
Fixes #2091
Calls would auto-deref any strong references when resolving the function
call. But, this auto-deref gets removed for units because of
7f269c5da866bd9da744ebdb7784641e1affce3f. For `new` calls, this
continued to work because they then got *re-resolved*. Calls did not
have this. This simply adds that re-resolution to function calls.
Technically this could apply to methods, but I couldn't trigger it in
Spicy, so I left it.