Function safe_arch::leading_zero_count_u32

#[must_use]pub fn leading_zero_count_u32(a: u32) -> u32

This is supported with target feature lzcnt only.

Count the leading zeroes in a u32.

assert_eq!(leading_zero_count_u32(u32::MAX), 0);
assert_eq!(leading_zero_count_u32(u32::MAX >> 3), 3);