Context

In the mtest.T.teardown function we count the number of sessions in progress on a client and verify that value is zero. But if a prose test resets the client, this assertion could be wrong.

Additional context: https://github.com/mongodb/mongo-go-driver/pull/2624#discussion_r4086038162

Definition of done

Sample sessions onto mtest.T when a client is reset. In the teardown the assertion becomes this:

	assert.Equal(t, 0, sampledSessionCount+sessions, "%v sessions checked out", sampledSessionCount+sessions)

Pitfalls

Uninvestigated