Add HTTP status to ServletRequestHandledEvent

Issue: SPR-12119
Polish Javadoc for @Sql and SqlScriptsTestExecutionListener
Document @Sql script support in the reference manual

 - Introduced a new "Executing SQL scripts" section in the Testing
   chapter with a subsection covering programmatic script execution via
   ResourceDatabasePopulator, ScriptUtils, etc. and a subsection
   dedicated to the new declarative support via @Sql.

 - Documented @Sql, @SqlConfig, and @SqlGroup in the "Annotations" and
   "Meta-annotation" sections.

 - Fixed broken cross-reference links to "false positives" with ORM tip.

 - Documented methods in JdbcTestUtils.

 - Improved layout and information in sections covering
   AbstractTransactionalJUnit4SpringContextTests and
   AbstractTransactionalTestNGSpringContextTests.

Issue: SPR-11849