fn normalize(r: *Managed, length: usize) void
Normalize a possible sequence of leading zeros.
[1, 2, 3, 4, 0] -> [1, 2, 3, 4] [1, 2, 0, 0, 0] -> [1, 2] [0, 0, 0, 0, 0] -> [0]
r: *Managed,
length: usize,