AtomicHashMapProxy calls Cache.getCacheConfiguration() triggering legacy config adaptation.

The following commit:
https://github.com/infinispan/infinispan/commit/672e91fab76c882498c24f5bf87d43b1c7654af5

adds a call to Cache.getCacheConfiguration(). In 5.1.x, this triggers a call to LegacyConfigurationAdaptor.adapt(...). In AS7, this has a consequence of:

• a performance penalty per new cache entry (we use an atomic map per session)
• an INFO log message containing a warning about the eviction configuration