Clean up imports and warnings
Revised naming for prototype inner beans to avoid excessive unique name calculation

Restored original singleton-only adaptInnerBeanName behavior, avoiding endless unique name calculation for every single prototype instance. Non-named inner BeanDefinition objects now suffixed with an identity hex code analogous to non-named XML bean definitions, largely avoiding naming collisions to begin with. After SPR-11246, post-processors can deal with unstable classes per bean name, so occasional collisions aren't a hard problem anymore.

Issue: SPR-11545
Added specific unit test for scoped-proxy target not being an autowire candidate

Issue: SPR-11548
Clean up ConfigurationClassPostProcessorTests
Investigate issue with @ComponentScan as meta-annotation

This commit introduces unit and integration tests that attempt to
reproduce the issue claimed by the reporter in SPR-11557. However, the
tests pass without any problems.

Issue: SPR-11557
Polishing
Add more tests for @ComponentScan as a meta-annotation

Issue: SPR-11557
Fix regression for newline separators in SQL scripts

Changes made in conjunction with SPR-9531, introduced a regression with
regard to support for using a single newline character as the statement
separator within SQL scripts. Investigation of the cause of this issue
resulted in the discovery of another, similar issue: support for
multiple newlines as a statement separator has been broken for years
but has gone unnoticed until now.

The reason that both of these issues have gone unnoticed is a result of
the fact that the test suite only executes SQL script integration tests
against HSQL DB, and HSQL does not care if two statements occur on the
same line; whereas, the H2 database will throw an exception if multiple
statements are included on the same line when executing an update.

This commit addresses both of these issues and provides further
enhancements to Spring's SQL script support as follows.

 - ScriptUtils now properly checks if the supplied script contains the
   custom statement separator or default separator before falling back
   to the 'fallback' separator (i.e., newline).

 - Introduced FALLBACK_STATEMENT_SEPARATOR constant in ScriptUtils.

 - ScriptUtils.readScript() no longer omits empty lines from the input
   file since a statement separator string may in fact be composed of
   multiple newline characters.

 - Introduced overloaded variants of splitSqlScript() and
   executeSqlScript() in ScriptUtils with smaller argument lists for
   common use cases.

 - Extracted AbstractDatabasePopulatorTests from DatabasePopulatorTests
   and introduced concrete HsqlDatabasePopulatorTests and
   H2DatabasePopulatorTests subclasses for testing against HSQL and H2.

 - Split ScriptUtilsTests into ScriptUtilsUnitTests and
   ScriptUtilsIntegrationTests for faster builds.

Issue: SPR-11560
Polishing
Add links to class-level Javadoc in JdbcTestUtils
Refine BrokerAvailabilityEvent behavior

Add accessor for brokerAvailable in AbstractBrokerMessageHandler
Ensure brokerAvailable is set even if eventPublisher is not
Add tests BrokerMessageHandlerTests

Turn off brokerAvailable when StompBrokerRelayMessageHandler stops
Actually stop message handling when brokerAvailable=false
Improve log messages

Issue: SPR-11563
Refine Reactor-based TCP client implementation

Configure explicitly use of SynchronousDispatcher instead of the one
used otherwise by default (RingBufferDispatcher). As a result TCP
optations are now scoped to Netty's threads.

Remove Environment field. It is no longer required to shut it down
since we're now using SynchronousDispatcher by default.

Replace connection.in() with connection.consume() when composing
connection handling. The former creates a Stream for further composing,
e.g. via map(), filter() but all we need is to read a message.

Provide additional constructor that aceepts a pre-configured Reactor
TcpClient instance.

Issue: SPR-11531
Rename ReactorNettyTcpClient to ReactorTcpClient

Even though Netty is a required dependency of reactor-tcp at present,
there is no hard dependency in the spring-messaging Reactor-based
implementation.