Check that there are no holes left by the removal of nsIContentPolicy

Since this commit: https://gitweb.torproject.org/https-everywhere.git/blobdiff/eb212b2e785b1760f976d2b7358a187f2adc82b1..445aa51a61fa2ec50998ac802c3d0c4261787929:/src/components/https-everywhere.js

To close #3882 (moved) , we should run more tests to ensure that no HTTP requests are escaping redirection.

We have done a bit of this without plugins, but we should also perform more and with plugins. Methodology:

Run a wireshark capture with the BPF set to "port 80" (or a protocol-level equivalent?).

Do a lot of browsing.

Filter out the HTTP Request packets.

See if any of them should have been rewritten.