Previously, both InfluxSampler and RubySampler were relying on the
`GC::Profiler.total_time` data which is the sum over the list
of captured GC events. Also, both samplers asynchronously called
`GC::Profiler.clear` which led to incorrect metric data because
each sampler has the wrong assumption it is the only object who calls
`GC::Profiler.clear` and thus could rely on the gathered results between
such calls.

We should ensure that `GC::Profiler.total_time` is called only in one
place making it possible to rely on accumulated data between such wipes.

Also, we need to track the amount of profiler reports we lost.