URLParser should not consider path of URLs with no host to start at the first slash...

URLParser should not consider path of URLs with no host to start at the first slash after the colon
https://bugs.webkit.org/show_bug.cgi?id=164555

Patch by Alex Christensen <achristensen@webkit.org> on 2016-11-09
Reviewed by Tim Horton.

LayoutTests/imported/w3c:

* web-platform-tests/url/a-element-expected.txt:
* web-platform-tests/url/a-element-xhtml-expected.txt:
* web-platform-tests/url/url-constructor-expected.txt:

Source/WebCore:

When we see a url that is only scheme:// we treated the // as the path.  Firefox did this with unrecognized schemes,
but based on https://github.com/whatwg/url/issues/148 they seem willing to change.  We had added similar behavior to
URL::parse, and I added this to URLParser in r206783 which this effectively reverts.

Covered by API and layout tests.

* platform/URLParser.cpp:
(WebCore::URLParser::parse):
Don't move m_userStart to m_pathStart back by two when we see an empty host.

Tools:

* TestWebKitAPI/Tests/WebCore/URLParser.cpp:
(TestWebKitAPI::TEST_F):

LayoutTests:

* fast/url/segments-expected.txt:
* fast/url/segments-from-data-url-expected.txt:
* fast/loader/url-parse-1-expected.txt:
* fetch/fetch-url-serialization-expected.txt:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@208508 268f45cc-cd09-0410-ab3c-d52691b4dbfc