2.26.168: translate-logical-pathname in probe-file*.
Had to refactor the asdf-pathname-test by decomposing it into small bits before I could understand what was going on. Some more robustness in find-system. Also, no build-report output-file when no *warnings-file-type*, and ABL support for build-report. Deprecate *asdf-verbose*. Have *verbose-out* be NIL (which is testable) rather than (make-broadcast-stream), which isn't quite, to signal no verbosity. That's both more useful while remaining backward-compatible.