[GTK] DumpRenderTree converts "file:///" to a path differently

[GTK] DumpRenderTree converts "file:///" to a path differently
https://bugs.webkit.org/show_bug.cgi?id=76631

Reviewed by Martin Robinson.

Tools:

DumpRenderTree should print "/" as the last path component if the
path is a lone slash instead of empty output.

* DumpRenderTree/gtk/DumpRenderTree.cpp:
(webViewConsoleMessage):

LayoutTests:

Unskipped a couple of tests after fix.

* platform/gtk/Skipped:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105587 268f45cc-cd09-0410-ab3c-d52691b4dbfc