test: remove the integration test (#306)

This test is evaluating one batch of real measurements. With the
upcoming change introducing committees and majorities, a single batch
of measurements is not enough to produce committees with the required
size. As a result, most measurements are rejected with
COMMITTEE_TOO_SMALL evaluation. In a recent test run, the number of
accepted measurements dropped from 14,512 to 2,530.

We could fix this test by evaluating all batches in one round,
but that would extremely slow down this test to the order of minutes.

Let's remove this test for now. If we find a need to test evaluation
results of real data, then I'd like to rework the `dry-run` CI step
to diff the dry-run output against a snapshot.

Signed-off-by: Miroslav Bajtoš <oss@bajtos.net>