Broaden integration test runs against Hibernate 6

[odrotbohm]

We should update our compatibility builds of the various Hibernate 6 releases currently in development to eventually resolve into this:

• Our 3.3 version tracking Hibernate 6.5 (currently in CR1, expected to GA end of April)
• Tracking 6.5 and 6.6 snapshots both on our 3.3 branch and our 3.2 maintenance branch
• Upgrade our 3.2 maintenance branch to the latest 6.4 release of Hibernate
• Additionally, build against Hibernate 6.2 as that's the long-term support branch contained in RedHat's JBoss EAP.

Setting up integration builds against Hibernate 7 is tracked in GH-3361.