Completes the JVM long-compatibility gap so clojure.test.check (and the
property-based suites built on it, e.g. data.codec) run on jolt.
A ^long is 64-bit but a Chez fixnum is only 61-bit, so the backend's fast fx
comparison / quot / min / max / inc / dec ops raised on a full-width long (one
from the PRNG or wrapping arithmetic). They now go through the jolt-l* macros
(host/chez/seq.ss): the fx fast path when the operands ARE fixnums, the generic
op otherwise — so e.g. ((fn [^long a ^long b] (< a b)) Long/MAX 1) is false, not
an error. Arithmetic +/-/* keep the raw fx ops (under *unchecked-math* they're
already the wrapping unchecked-*).
Also fixes unsigned-bit-shift-right: it was an arithmetic (sign-propagating)
shift, now a logical shift over the 64-bit two's-complement window, so
(unsigned-bit-shift-right -1 1) is 2^63-1 like the JVM.
Result: test.check 1.1.3 loads and runs (generators, quick-check, shrinking);
data.codec's base64 property suite passes (12/12 defspecs; the 2 deftests check
clojure.lang.IFn$OLLOL, a JVM primitive-fn interface, N/A). Both added to
docs/libraries.md + the site.
re-mint (backend/seed). make test green (+3 corpus rows, 0 new divergences,
numeric gate updated to the jolt-l* ops), shakesmoke byte-identical.