Fix the integration test from crashing

Sessions are expected to only have one running query (perhaps this is a
bug). So we need to make a new session for each of the benchmark runs,
timing only the running part.

cayley_test.go

@@ -363,12 +363,18 @@ func runBench(n int, b *testing.B) {
 	if err != nil {
 		b.Fatalf("Failed to parse benchmark gremlin %s: %v", benchmarkQueries[n].message, err)
 	}
+	b.StopTimer()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		c := make(chan interface{}, 5)
+		ses := gremlin.NewSession(ts, cfg.Timeout, true)
+		// Do the parsing we know works.
+		ses.InputParses(benchmarkQueries[n].query)
+		b.StartTimer()
 		go ses.ExecInput(benchmarkQueries[n].query, c, 100)
 		for _ = range c {
 		}
+		b.StopTimer()
 	}
 }