- DefaultBootstrapContext and DefaultCacheAwareContextLoaderDelegate
   are now public classes in the 'support' subpackage.

 - Introduced getCacheAwareContextLoaderDelegate() in
   AbstractTestContextBootstrapper as an extension point for configuring
   custom ContextCache support.

 - Introduced reflection-based createBootstrapContext() utility method
   in BootstrapUtils; TestContextManager now delegates to BootstrapUtils
   in order to avoid package cycles.

 - Introduced logStatistics() method in the ContextCache API and defined
   statistics logging category as a constant.

 - DefaultCacheAwareContextLoaderDelegate now delegates to
   ContextCache.logStatistics().

Issue: SPR-12683