-8f64 is N_UN(TK_MINUS) wrapping a float-typed N_INTLIT; the wwstage
exprfloatkind must recurse through the unary into the N_INTLIT-float
arm. Two rows: a true-case catcher (g(-8.0) == -8f64 -> 1; pre-fix the
literal never reaches X0 so the compare is always false and g(-8.0)
wrongly returns 0, plus a cs!=ww .s divergence) and a false-case
control (g(8.0) -> 0). Both pass byte-identically on the fix.
Table-driven, modelled on 953: each row does (a) cstage build+run+exit
and (b) w6c vs w6c_ww .s cmp. Rows cover FACE X (0f64 compare false +
true case, 8f64 arith) and FACE Z (tuple-field f64 compare) plus the
let-bound control that was already correct. Fails on master e784968
(x_cmp_false 1!=0, x_arith 100!=80 + byte-id divergence, z_tuple_field
5!=9); passes on the fix.
