BUGFIX-66

Bug 18: The Bit That Decides It

• We are testing whether br(x) < br(y) where br denotes bit reversal.
• Bit reversal swaps bit i with bit 63-i (for 0 <= i <= 31).
• We test br(x) < br(y) using the least significant bit that is different in x and y.
• After bit reversal, this is the most significant bit that is different.

Fix The Tiny Bug In This Go Code: