This reverts commit 2f16f2d1.

In the final Tor Browser 5.5 release the window resizing issue that
caused issues for us in the automated test suite should be fixed.

Will-fix: #10892

Will-fix: #10983

Fix-committed: #10926

Fix-committed: #10850

Fix-committed: #5472

Fix-committed: #9374

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

Will-fix: #10926

Fix-committed: #10925

Fix-committed: #9087

Also:
* Don't use class variables (@sshd) unnecessarily.
* Ruby does not support "keyword" style parameter assignment
  (sshd_host, sshd_port).

Fix-committed: #10340

Fix-committed: #10782

Any random number in the range can of course already be in use.

They try to do the same thing, but the former uses uglier parsing
(imho) and fails if the test suite is run as a non-root user since
ifconfig is in /sbin, which generally isn't in such users' PATH:s.

Fix-committed: #10907

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.

Hopefully a test writer would think twice before re-using this name
when creating a new disk, so we won't repeat #10907.

Refs: #10907

In fact, "current" is already used as the disk name internally for our
snapshots, and this would overwrite this one, including all snapshots.

Will-fix: #10907

Bugfix on 2.0~beta1.

Will-fix: #10925

While running tests for test/10782-restart-seahorse-in-same-manner,
I've seen the "I start Seahorse via the Tails OpenPGP Applet" step
fail every time due to "FindFailed: can not find GpgAppletIconNormal.png
on the screen", apparently because the OpenPGP Applet icon was a tiny
bit truncated. With this small change to the image, it passes just fine.

refs: #10782

Will-fix: #5472

Fix-committed: #10945