Test implementation change: Let `TestNessieCompatibilityExtensions.upgrade()` not use RocksDB

[snazy]

Issue description

RocksDB requires native libraries, which (natually) depend on the RockDB version being used.

In the compatibilty tests, and especially the tests for those, RocksDB is being used.

Native libraries are JVM global resources and not isolated per class loader.

The recent RocksDB version bump made it obvious, that RocksDB, due to its usage of native libraries, is not a good candidate for these tests, as the native libraries of two different RocksDB versions are incompatible.

It's recommended to let the tests for the compatibility-tests not use RocksDB. H2 configured using a file location feels like a good candidate over other, more heavy weight to setup databases.