[PATCH] ADT: Shave a pointer off of SmallVector<T, 1>

[Duncan P. N. Exon Smith]

> On 2015 Jun 30, at 17:34, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
> 
> Note that `SmallVector<T, 0>` has the same memory footprint as
> `SmallVector<T, 1>`, which seems like a bug to me.  We should probably
> fix that too.

(Just as a follow-up, I looked into this and it's pretty tough without
sacrificing something else.  Given that we have very little code using
`SmallVector<T, 0>`, it's probably not worth fixing.)