[PATCH v1] unit-tests for request first-line parser.

One of our users uncovered a nasty bug in 3.1 today. Squid hangs on some
simple requests.

On investigating I found that an update to make it return errors had
used the wrong result code in a few places. Causing it to loop trying to
read more data and complete the first line which was already complete.

The parser function also has no unit tests to verify correct operation.
Included in this patch is a draft outline for some unit-tests.

If anyone has suggestions or knowledge of other input cases please speak
up; good, bad AND ugly examples wanted.

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE9 or 3.1.7
   Beta testers wanted for 3.2.0.1