PR libfortran/97581 - clean up size calculation of random generator state

PR libfortran/97581 - clean up size calculation of random generator state

The random number generator internal state may be saved to/restored from
an array of integers.  Clean up calculation of needed number of elements
to avoid redefiniton of auxiliary macro SZ.

libgfortran/ChangeLog:

	* intrinsics/random.c (SZ_IN_INT_4): Define size of state in int32_t.
	(SZ_IN_INT_8): Define size of state in int64_t.
	(SZ): Remove.
	(random_seed_i4): Use size SZ_IN_INT_4 instead of SZ.
	(random_seed_i8): Use size SZ_IN_INT_8 instead of SZ.