mmaprototype: populate conf.NumVoters to conf.NumReplicas if 0

Previously, MMA used the given span config directly. However, the comment on
config.NumVoters specifies that if it is set to zero, the voter replica count
should default to NumReplicas, which is usually handled by
SpanConfig.GetNumVoters().

Author: wenyihu6

pkg/kv/kvserver/allocator/mmaprototype/constraint.go

@@ -252,6 +252,9 @@ type internedLeasePreference struct {
 func makeNormalizedSpanConfig(
 	conf *roachpb.SpanConfig, interner *stringInterner,
 ) (*normalizedSpanConfig, error) {
+	if conf.NumVoters == 0 {
+		conf.NumVoters = conf.NumReplicas
+	}
 	var normalizedConstraints, normalizedVoterConstraints []internedConstraintsConjunction
 	var err error
 	if conf.VoterConstraints != nil {