Prior to this commit several test classes named "*Test" were not
recognized as tests by the Gradle build. This is due to the configured
inclusion of '**/*Tests.*' which follows Spring's naming convention for
test classes.

This commit addresses this issue by:

 - Renaming real test classes consistently to "*Tests".
 - Renaming internal test classes to "*TestCase".
 - Renaming @WebTest to @WebTestStereotype.
 - Disabling broken tests in AnnoDrivenStaticEntityMockingControlTest.
 - Modifying the Gradle build configuration so that classes ending in
   either "*Tests" or "*Test" are considered test classes.

Issue: SPR-11384

Starting with Spring 3.1 applications can specify
contextInitializerClasses via context-param and init-param in web.xml;
however, there is currently no way to have such initializers invoked in
integration testing scenarios without writing a custom
SmartContextLoader. For comprehensive integration testing it should
therefore be possible to re-use ApplicationContextInitializers in the
Spring TestContext Framework as well.

This commit makes this possible at the @ContextConfiguration level by
allowing an array of ACI types to be specified, and the out-of-the-box
SmartContextLoader implementations invoke the declared initializers at
the appropriate time.

 - Added initializers and inheritInitializers attributes to
   @ContextConfiguration.

 - Introduced support for ApplicationContextInitializers in
   ContextConfigurationAttributes, MergedContextConfiguration, and
   ContextLoaderUtils.

 - MergedContextConfiguration stores context initializer classes as a
   Set and incorporates them into the implementations of hashCode() and
   equals() for proper context caching.

 - ApplicationContextInitializers are invoked in the new
   prepareContext(GenericApplicationContext, MergedContextConfiguration)
   method in AbstractGenericContextLoader, and ordering declared via the
   Ordered interface and @order annotation is honored.

 - Updated DelegatingSmartContextLoader to support initializers.
   Specifically, a test class may optionally declare neither XML
   configuration files nor annotated classes and instead declare only
   application context initializers. In such cases, an attempt will
   still be made to detect defaults, but their absence will not result
   an an exception.

 - Documented support for application context initializers in Javadoc
   and in the testing chapter of the reference manual.

Issue: SPR-9011