Migrate Hibernate ORM EntityTest, SessionFactoryTestCase unit test to use new ORM Session signature

Find tests that mention WFLY-16178 and update the test code to include the tests excluded as per comments that references WFLY-16178.

Reproduce steps:
cd testsuite/integration/basic/
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.jpa.hibernate.entitytest.EntityTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.jpa.hibernate.sessionfactorytest.SessionFactoryTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.hibernate.Hibernate2LCacheStatsTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.hibernate.Hibernate4NativeAPIProviderTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.hibernate.Hibernate4NativeAPIEnversTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.hibernate.envers.Hibernate4NativeAPIEnversTestCase
mvn install -Dts.ee9 -Dtest=org.jboss.as.test.integration.hibernate.naturalid.HibernateNativeAPINaturalIdTestCase

Note the following api differences:

ORM 6:

<T> T load(Class<T> theClass, Object id);

ORM 5.3:

<T> T load(Class<T> theClass, Serializable id);

The "Session.save" method also has similar differences (e.g. ORM 5.3 signature 'java.io.Serializable org.hibernate.Session.save(java.lang.Object)`).

Currently, we see test failures like:

Caused by: java.lang.NoSuchMethodError: 'java.io.Serializable org.hibernate.Session.save(java.lang.Object)'
at deployment.jpa_entitytest.jar//org.jboss.as.test.integration.jpa.hibernate.EntityTest.createCustomer(EntityTest.java:135)

The above failures should be resolved by recompiling the org.jboss.as.test.integration.jpa.hibernate.entitytest.EntityTestCase test sources against Hibernate ORM 6.0.