Add print-object infrastructure for constituents (used while debugging).

Take advantage of recent ASDF 1.367 enhancements in pathname computation, when available.

Don't normalize away last component in a component name that has dots.

Functionalize a few macros,
make constituent designators slightly more readable,
fix a typo,
fix a compiler warning in a test.

* Load-source-op planning is broken, especially in how it trickles to
 other systems you depend on. Use load-op for planning, but have it
 perform like load-source-op on our instrumented files.
* Fix :conc-name nil in defstruct

Cleanup: remove an XCVB-only function.
Tweak normalize-pathname-directory-component.
Add TODO: use a real code-walker / CL evaluator

This commit is related to XCVB's change 85a7d660021b5175c131122ef21c2e334afc54ab, which updates XCVB to use ADG's fine-grain-instrumented-load when converting from asdf-to-xcvb.

2- suppress style-warnings due to the use of some variables being commented out

  - Added instrumentation for #. and #S
  - Potentially dangerous heuristics for defvar and defconstant
  - Improved handler for defstruct
  - New unit tests
  - Some cleanup of old code

- ADG doesn't see ASDF modules, causing ADG to mix up (:file "pkgdcl")
  in module "qres-core" with the (:file "pkgdcl") in module "pas/clr",
  for example.  The fix is to use the component-pathname instead of the
  component-name.  The component-pathname is annoyingly longer than
  the component-name however, so I'd be happy for a different solution.
- Also fixed grovel.lisp:operating-on-asdf-component-constituent to call
  signal-new-internal-symbols.  Otherwise ADG will confuse which package
  an internal symbol belongs to.

(changes actually by fare)

A few :hash-key should have been :hash-keys.
A couple of :for = statements made into a (let ...)
to allow for their being after an :until.