Remove unneeded reassignment of `r`

core/math/rand/normal.odin

@@ -115,13 +115,6 @@ norm_float64 :: proc(r: ^Rand = nil) -> f64 {
 		0.008624485, 0.005548995, 0.0026696292,
 	}
 
-	r := r
-	if r == nil {
-		// NOTE(bill, 2020-09-07): Do this so that people can
-		// enforce the global random state if necessary with `nil`
-		r = &global_rand
-	}
-
 	for {
 		j := i32(uint32(r))
 		i := j & 0x7f