private void reduceFieldLiteralBoosts(Schema schema) {
        for (SDField field : schema.allConcreteFields()) {
            if (field.getLiteralBoost() < 0) continue;
            reduceFieldLiteralBoost(field, schema);
        }
    }
Ensures there are field boosts for all literal boosts mentioned in rank profiles.
This is required because boost indices will only be generated by looking
at field boosts
config-model/src/main/java/com/yahoo/schema/processing/LiteralBoost.java