Refs #6136 - Adds test for elgg_http_url_is_identical
resolved the todo of using elgg_normalize_url in the
http_url_is_identical and also fixing the bug where url2 did not get
site_url prepended
Merge pull request #6145 from Srokap/pr/6136_test

resolved the todo of using elgg_normalize_url in the http_url_is_identical and also fixing the bug where url2 did not get
site_url prepended