FactorialWorkingContext​(System.​Int32)

The factorial's working context: twice precision's digits, and no bound on
the exponent. The caller's context bounded it, so an intermediate past its ceiling or below
its floor lost its digits though the value fit: at the default precision (400.5)! was
+oo, where it is 1.28e870. One per precision, so that the constants the library
caches per context stay few. https://github.com/asc-community/AngouriMath/issues/1614