[2.0] Fixes race between reading into cache and commit updating the cache

This is supposed to go into 2.1, but since the problem exists in all versions of Neo4j, and the fix is the same for 2.0 as 2.1 I'm taking this via 2.0.
This test case has played its part. It very specifically tests for an issue that has since been fixed. I talked this through with @tinwelint and we came to the conclusion that it was better to remove this test case than try to rewrite it so that it passes with the new locking in place.