Remove Calc bignum remnants

Remove Calc bignum remnants

* lisp/calc/calc-macs.el (Math-natnum-lessp):
* lisp/calc/calc-ext.el (math-norm-bignum, math-compare-bignum):
* lisp/calc/calc-math.el (math-zerop-bignum)
(math-scale-bignum-digit-size): Remove.

* lisp/calc/calc-bin.el (math-integer-log2, calcFunc-rot, math-clip):
* lisp/calc/calc-comb.el (math-prime-test, calcFunc-prfac)
(calcFunc-totient, calcFunc-moebius):
* lisp/calc/calc-ext.el (math-gcd):
* lisp/calc/calc-funcs.el (calcFunc-betaB):
* lisp/calc/calc-math.el (math-nth-root-int-iter, calcFunc-ilog):
Replace Math-natnum-lessp with <.