Fix restart-tor and tor-has-bootstrapped semantics vs. test suite on Jessie

Originally created by @intrigeri on #10537 (Redmine)

On feature/jessie, the “Tor has bootstrapped” code has been revamped and ported to systemd; some optimization that has gone into it apparently breaks assumptions that the automated test suite was relying on already, and/or that code added for #9516 (closed) started relying on. We should identify what exactly the test suite needs, and then check whether we’d better change the semantics of restart-tor/tor-has-bootstrapped to satisfy the test suite’s needs, or instead have the test suite take into account the changed semantics somehow.

Feature Branch: feature/jessie

Related issues

• Related to #9516 (closed)
• Blocks #7563 (closed)