1.0.43.56: make %INSTANCE-TYPEP always-translatable

 One way to make an SBCL that builds but cannot build itself is
 to change the compiler so that it fails to eliminate a full call
 to %INSTANCE-TYPEP.

 This doesn't change that, but at least makes such hosts fail in a
 place where the issue is easier to figure out than hitting "undefined
 function: %INSTANCE-TYPEP" during cold-init.