Verify ServletCtxAware beans are processed in WAC tests

SPR-11145 claims that ServletContextAware beans declared in an
ApplicationContext loaded for an integration test by the TestContext
framework (TCF) do not have their setServletContext() methods invoked
if the tests are executed manually using JUnit 4.11.

This commit verifies that such ServletContextAware beans are processed
properly regardless of how the test was launched. Specifically:

 - A ServletContextAwareBean has been introduced.

 - BasicAnnotationConfigWacTests has been retrofitted with a
   ServletContextAwareBean in its context.

 - ServletContextAwareBeanWacTests has been introduced to execute
   BasicAnnotationConfigWacTests manually via JUnitCore.

Issue: SPR-11145