test(rewrite): cover every shell spelling of an unsafe consumer flag

The consumer-flag cases were a hand-maintained list that grew one literal per
review round, so each new spelling was found by review rather than by a test.

Generate the spellings from SAFE_PIPE_CONSUMERS instead: every unambiguous
long-option prefix getopt_long accepts, each in bare, double-quoted,
single-quoted, backslash-escaped and =value form, and every unsafe short flag
bare, quoted, escaped and bundled. A consumer added to the table later is
covered on arrival.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>