Fix flaky special char specs by not using `with_history` twice per test
Fix flaky special char specs by not using `with_history` twice per test

There's something funny occasionally happening when `with_history` is
used twice in the same test. It seems to be happening more frequently
since asynchronous mode was enabled by default. My guess is it has
something to do with the `C-c` keys being sent toward the end not
consistently terminating the prompt. But I'm really not sure how it
would ever get into a `then` block like it seems to:

```
Failure/Error: wait_for { session.content }.to eq('echo "hello\nworld"')

  expected: "echo \"hello\\nworld\""
       got: "then> echo \"hello\\"
```

Sticking to only one `with_history` per terminal session (per test)
seems to fix the flakiness.

I also removed an old test case because I could not understand why it
was necessary and so couldn't write a good description for it. Could be
we'll need to add it back in at some point.

zsh-users/zsh-autosuggestions,tarruda/zsh-autosuggestions,zsh-users/zsh-autosuggestions