In particular this enables the retry magic we added for the "Tails
documentation" launcher to the "Report and Error" case since the code
now is refactored and used in all cases.

Normally we always start the browser via the 'I start the Tor Browser'
step, which sets @torbrowser, but this step does it too, so let's set
it there as well.

We have decided to remove I2P (Refs: #11276) due to our failure of
finding someone interested in maintaining it in Tails.

Will-fix: #12263

Will-fix: #12131

This is a fixup on 2dddaca0.

Test suite: start adjusting for the way additional settings are handled in the new Greeter (refs: #12055).

I.e. the tests are done using a tool *different* from MAT, the tool
being tested here.

Refs: #11901

Because MAT doesn't clean PDFs anymore. :_(

Will-fix: #11901

We previously relied on Sikuli, and the image was made outdated thanks
to our donation campaign. No more!

Will-fix: #11911

So now we can use snapshots in the affected scenarios, which this commit
also implements.

Will-fix: #5571

The Pictures & friends directories are not automatically created on
feature/stretch currently, and thus gnome-screenshot saves screenshots to $HOME.

Given these directories would not be persistent, IMO it's a feature to avoid
encouraging users to store stuff in there. So I'm simply adjusting the test to
reflect how it now works.

refs: #8183

refs: #6841

This `assert` will always pass since `mode` always is either one of
two String:s. The intention was clearly `assert_equal`.

Will-fix: #10926

Instead of waiting a long time, let's just check that networking truly
is disabled, in the same way we do for the MAC spoofing tests -- after
all the code for the "Diable networking" feature actually originates
from the MAC spoofing feature. This way we do not have to introduce a
static wait for 120 seconds, and we do not need the anti-test.

In Jessie, org.gnome.gnome-screenshot.auto-save-directory is empty
since the default is sensible, ~/Pictures. To save the removed
scenario we'd have to set it explicitly, which seems stupid. Besides,
the 'A screenshot is taken when the PRINTSCREEN key is pressed'
scenario is already testing that GNOME Screenshot saves into this
directory, which is enough.

We want to change the owner of the symlink, not the file it points
to. Yes, this made the secret leak every time. :)

I.e. as amnesia, which doesn't have it in its PATH, and must use
sudo. This shouldn't be needed, but is more realistic if we switch the
approach later.

... and pave the way for adding more options than the user to execute
the command as.

Waiting for a random amount of time just seems like it could cause us
to miss phone-home type traffic.

Will-fix: #9402

That is, instead of sharing folders we do not necessarily own and that
may have bad permissions, we create the share source in the temporary
directory and copy/generate the necessart files there instead.