This reverts commit 036e340bd9.
Problems with this one were:
- Broken event timings. m_prevtime wasn't reset to m_curtime in
TracingPlugin::handleSingleIP(), resulting in a large deltatime
being recorded for the second event, too. This effectively
doubled the experiment's start time.
- Code repetition (copy/pasted for special handling of first event),
making planned changes (advanced tracing for IP events) more
difficult.
- Unnecessary additional tracing-plugin interface method.
Change-Id: I4b74d1a3f4563aabe6626399f9b30a2171b4c285