Tests file system project mappings.


Running: testProjectBasedMapping
Adding file system.
UISourceCode uri to url mappings:
    file:///var/www/html/foo.js -> http://127.0.0.1:8000/inspector/resources/html/foo.js
    file:///var/www/html2/bar.js -> http://127.0.0.1:8000/inspector/resources/html2/bar.js