GroupSequenceProvider#getValidationGroups() is called 2 times per validation

This is a follow-up of https://discourse.hibernate.org/t/when-using-a-groupsequenceprovider-why-is-it-called-3-times-and-why-the-first-time-with-a-null-validation-instance/873 .

We could call it only once and pass it to the next methods. We could also use the redefined group sequence being not null as the condition instead of relying on beanMetaData.defaultGroupSequenceIsRedefined() for the second call.