Fix bug in deftransform where the case for x86 and num-high > random-fixnum-max was never used. We now always use the bignum multiply code for all platforms and use that for all cases for which the deftransform applies. Simplify the constant-continuation case too so we don't have to the check. I think the bignum multiply version does not have the bias problem that rem has. code/rand-mt19937.lisp: Change the RANDOM function to compute the same value as the deftransform would. general-info/release-19f.txt: Update Make a note that both the function and the deftransform should be synchronized to match. This change also changes the sequence of numbers produced.