Deprecate mutable aspects of MethodParameter

[philwebb]

Issue #23352 has shown that the mutable nature of MethodParameter can cause problems. One particularly unusual aspect is that getContainingClass() can change as a side effect of calling GenericTypeResolver.resolveParameterType().

Internally, we don't actually mutate MethodParameter instances that often so it's possible that we could deprecate the mutation methods in favor of calls that return a new instance.

[philwebb]

@jhoeller I have a branch here with a fix https://github.com/philwebb/spring-framework/tree/gh-23385. It will need to be rebased when #23352 is committed.

[jhoeller]

@philwebb This looks alright to me. Feel free to bring a corresponding commit into master ASAP.