Implement assembly routine for xoroshiro update function

Describe the bug

The function xoroshiro-gen is an inline function that calls the VOP that computes a new 64-bit random number and the next state. This is fairly large, so everywhere it gets inlined, we have quite a bit space used.

To reduce code size, we should implement a Lisp assembly routine that performs the update. Then xoroshiro-gen would call the routine and be relatively short. Thus, code size is reduced.

Desktop (please complete the following information):

• OS: All
• Version: All versions after the xoroshiro128+ generator was implemented.

Additional context

When we used MT-19937 as the generator, we had an assembly routine. We should do the same.