ISPN-2932 Verify that preloading a read only index in a cache will never...

... hit the cacheloader

https://issues.jboss.org/browse/ISPN-2932



I'm not sure if this strategy can give us a strong guarantee of not having some loading still happening:
- Windows will not remove memory mapped files until the JVM shuts down
- We're not sure if the test is working but actually did try to load first, and not succeeding it then hits entries in the datacontainer as second choice

You probably want to avoid deleting it at this stage and access some statistics; not sure if we have a statistic like this, worst case you can wrap the CacheLoader with a decorator.. or use Byteman to not write any code :)