function removeOneSpacing(v) {
  v &= 0x55555555;
  v = (v ^ (v >> 1)) & 0x33333333;
  v = (v ^ (v >> 2)) & 0x0f0f0f0f;
  v = (v ^ (v >> 4)) & 0x00ff00ff;
  v = (v ^ (v >> 8)) & 0x0000ffff;
  return v;
}
Removes one bit of spacing between bits. This is the opposite of insertOneSpacing.

Example:
 input: 20
 input (binary):  10100
                   ^ ^ (removed)
 output (binary): 110
 output: 6

@private
@param {number} v A 32-bit unsigned integer.
@returns {number} A 16-bit unsigned integer.
@see {@link https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/}