Judge a leaf module on one healthy reading, a core module on three (hq issue 524)

ADR 0282 decided readings by class and ADR 0304 took a leaf module to
one, but the gate never learned it: every build, leaf or core, needed
three readings over at least two minutes, so a container module that
was healthy at once still waited about two and a half minutes on its
first machine. The number of readings and the settle time now follow
the module's class: three after two minutes for the controller's own
path and the resolver, one for every other module. Tests that judge a
gate's other rules keep leaf modules on three readings.

cmd/mesh-controller/same_source_test.go

@@ -162,6 +162,7 @@ func TestABusRebuiltFromAnUnchangedSourceDemandsNoBusStep(t *testing.T) {
 // A plan's build made from the source every machine running the module runs is not sent and not
 // judged: nothing moves. A build of a changed source is sent to its first machine, gated, as before.
 func TestAPlanSendsNothingForAnUnchangedSource(t *testing.T) {
+	judgeLeavesAsTheCore(t)
 	for _, tc := range []struct {
 		name   string
 		source string