Closes gh-23747

Prior to this commit and following changes done in d27b5d0a, the CORS
response headers would not be added for SockJS-related requests, even
though a CORS configuration had been applied to SockJS/WebSocket.
This was due to a missing case in our implementation: calling
`AbstractHandlerMapping#getHandlerInternal` can return a Handler
directly, but also a `HandlerExecutionChain` in some cases, as explained
in the Javadoc.

This commit ensures that, when checking for existing CORS configuration,
the `AbstractHandlerMapping` class also considers the
`HandlerExecutionChain` case and unwraps it to get the CORS
configuration from the actual Handler.

Fixes gh-23843

Centralized maxInMemorySize exposed via CodecConfigurer along with
ability to plug in an instance of MultipartHttpMessageWrite.

Closes gh-23884

See gh-23884

See gh-23884

- Add maxInMemorySize property to Decoder and HttpMessageReader
  implementations that aggregate input to trigger
  DataBufferLimitException when reached.

- For codecs that call DataBufferUtils#join, there is now an overloaded
  variant with a maxInMemorySize extra argument. Internally, a custom
  LimitedDataBufferList is used to count and enforce the limit.

- Jackson2Tokenizer and XmlEventDecoder support those limits per
  streamed JSON object.

See gh-23884

See gh-23769

At present, MockCookie doesn't preserve expires attribute. This has a
consequence that a cookie value set using
MockHttpServletResponse#addHeader containing an expires attribute will
not match the cookie value obtained from
MockHttpServletResponse#getHeader, since the expires attribute will get
calculated based on current time.

This commit enhances MockCookie to preserve the expires attribute.

Closes gh-23769

This commit provides opt-in enablement of Gradle's remote build
cache. When the GRADLE_ENTERPRISE_URL environment variable is set, its
build cache node will be used as a source of cached output. If both
GRADLE_ENTERPRISE_CACHE_USERNAME and GRADLE_ENTERPRISE_CACHE_PASSWORD
are also set, task output produced by the build will be pushed to the
build cache node for use by subsequent builds.

Closes gh-23883

Closes gh-23871

Closes gh-23870

See gh-23878

Closes gh-23874

See gh-23864

Closes gh-23873

See gh-23869

Closes gh-23869

Prior to this commit, TransactionalOperator::transactional did not close
the transaction when cancelled.

Closes gh-23864

Previously, when a project's jar was an input into a test task, a
cache hit required the current build to be using the same JDK as the
one that created the cache entry. This was due to the Created-By
entry in the jar's manifest which will vary if JDKs with different
values for the java.version and java.specification.vendor version are
used.

This commit configures normalization of the runtime classpath to ignore
META-INF/MANIFEST.MF, thereby allowing a cache hit when the tests were
previously run on a different JDK than the one being used now. Typically
this is a different update release being used on a CI agent and a
developer's machine. This change will therefore improve the likelihood
of a cache hit once remote caching has been enabled.

Closes gh-23872

See gh-23871

See gh-23870

Update `AnnotationTypeMappings` so that a custom `RepeatableContainers`
instances can be used. Prior to this commit, only standard repeatables
were used when reading the annotations. This works in most situations,
but causes regressions for some `AnnotationUtils` methods.

Fixed gh-23856

Closes gh-23780

Closes gh-23777

See gh-23803

Make use of the new getAvailableExtensionNames() method.

Closes gh-23799

This commit makes the XpathRequestMatchers constructor protected again
in case users have extended this class.

Prior to this commit, several of the methods in XpathRequestMatchers
declared unused type parameters (e.g., <T>). This was obviously the
result of copying an existing method that actually needs the type
parameter for proper casting.

For example, the following ...

public <T> RequestMatcher exists() {
    // ...
}

... should actually be declared without <T>, since T is not used in the
implementation or in the return type:

public RequestMatcher exists() {
    // ...
}

This commit removes all unused type parameter declarations in
XpathRequestMatchers.

Side Effects:

Now that we have removed the unused type parameter declarations, users
will see the following side effects if they had previously declared a
type argument when invoking such methods.

- Java: an "Unused type arguments for the non generic method ..."
  warning will be generated by the compiler, but the code will continue
  to work unmodified.

- Kotlin: a "Type inference failed: Not enough information to infer
  parameter T in fun ..." compiler error will be raised, causing the
  code to no longer compile (see
  https://youtrack.jetbrains.com/issue/KT-5464). Removal of the type
  argument declaration will allow the code to work correctly again.

Closes gh-23860