Predicate of :NAMED defstruct must respect pseudo-type-hierarchy.
Prevent meta-conditions from cluttering some test output.

- The handlers for style-warnings had style-warnings in them.
- Don't throw through COMPILE. It prints that compilation was aborted.

This is a drop in the ocean - still way too noisy.
Derive type for POSITION{-IF,-IF-NOT} in non-hairy constant vector.
Improve type declarations in SET-CMT-ENTRY