bug#7174: 23.2; `last' can be made faster by using `length'

[IRIE Shinsuke]

At Wed, 13 Oct 2010 19:30:55 -0400,
Glenn Morris wrote:

> (I assume it is still faster than the original, BTW?)

I examined that.

The new `last' is still faster than the original even though it uses
`safe-length', except for particular cases as follows:

  (last nil 0)   (last '(foo) 0)   (last '(foo))

Here, '(foo) is a list of one element. In these cases, it's 2-5% slower.
If LIST has 1000 elements, 4-8 times faster.

IRIE Shinsuke