Enable persistence cache on integration tests

This commit enabled persistence cache on integration tests so we can
add integration tests moving forward that test edge cases with persistence
cache issues.

This also speeds up integration tests a bit, further improvments can be done by reducing
re initialize of repository as well as amount of cache clearing.
Fix EZP-21741: Persistence cache not cleared on transaction rollback
Merge pull request #561 from ezsystems/cache_rollback_clear

Fix EZP-21741: Persistence cache not cleared on transaction rollback