A variable referencing the same other variable more than once is not a
cycle, so memoization alone still leaves the OUTPUT exponential in size
(each level's re.sub concatenates the memoized child result multiple
times). Adds a shared output-size budget, checked before using either
a cached or freshly-computed result.
Also ignore the runtime shortcuts.json data file, and fix the fan-out
test's assertion, which was checking against a vacuous condition.
digital-garbage
d80be3c327