Fix location.protocol handling [M1328894]

[classilla]

This apparently resolves some W3C test failures and some sites like https://www.clickondetroit.com/in-the-d which has no content in FPR11.

[classilla]

Note: the data: cases in the referenced W3C tests also fail on mainline Firefox intentionally. All the other tests now pass.

http://w3c-test.org/html/browsers/history/the-location-interface/location-protocol-setter-non-broken.html
http://w3c-test.org/html/browsers/history/the-location-interface/location-protocol-setter-non-broken-weird.html

[classilla]

Fixed in 4cdf931 and 9ca3c07