SIP URI comparison fixes.

This initially was created to work around the issue of
using a string comparison instead of a binary comparison
for IP addresses. It evolved a bit when test cases were
created and it was discovered that comparison of URI
parameters was not working exactly as it should.

sip_uri_cmp() and its helpers have been moved to reqresp_parser.c
and a new test has been added.

(closes issue #17662)
Reported by: oej

Review: https://reviewboard.asterisk.org/r/792



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@278980 65c4cc65-6c06-0410-ace0-fbb531ad65f3