[Review]: Fix Integer Division Expansion special case of divide by 1

[Aditya Nandakumar]

I don’t have a test case before and after for in-tree target but it fixed test for out of tree target.
The logic is what I am pointing out is wrong - we need to check if CTLZ(divisor) == Num_bits - 1 rather than CTLZ(divisor) - CTLZ(dividend).
> On Jul 6, 2015, at 2:29 PM, Michael Ilseman <milseman at apple.com> wrote:
> 
> Do you have a test case that demonstrates the failure before-hand, and the fix after? 
> 
>> On Jul 2, 2015, at 12:26 PM, Aditya Nandakumar <aditya_nandakumar at apple.com> wrote:
>> 
>> <DiffIntUnsignedDivision.patch>
>