Makefile: disable postgres fsync in the test container

This change turns off fsync on the postgres container used for tests. This
reduces migration time significantly when initializing new satellite
databases.

The change also includes a new benchmark for satellite initialization in
testplanet.

$ benchstat old.txt new.txt name                       old time/op  new time/op  delta
Run_Satellite/Postgres-16   1.36s ± 0%   0.08s ± 0%   ~     (p=1.000 n=1+1)

Change-Id: Ic954767133864770cf652b0dfdcd6b109a167b5f

docker-compose.tests.yaml

@@ -5,6 +5,7 @@ version: "3.4"
 services:
   postgres:
     hostname: postgres
+    command: -c fsync=off
     image: postgres
     environment:
       POSTGRES_USER: postgres

private/testplanet/run_test.go

@@ -25,6 +25,10 @@ func TestRun(t *testing.T) {
 	})
 }
 
+func BenchmarkRun_Satellite(b *testing.B) {
+	benchmarkRunConfig(b, testplanet.Config{SatelliteCount: 1})
+}
+
 func BenchmarkRun_StorageNode(b *testing.B) {
 	benchmarkRunConfig(b, testplanet.Config{StorageNodeCount: 4})
 }