[llvm] [mlir] [mlir] Mark `isa/dyn_cast/cast/...` member functions deprecated. (PR #90413)

[Christian Sigg via llvm-commits]

chsigg wrote:

This passes the Windows CI now which uses the same Visual Studio 2019 version as the CI build that previously broke. This is expected because it no longer uses the `LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH` macro. I did see cl.exe running out of heap space on previous revisions building flang, but that is likely an unrelated transient failure.

https://github.com/llvm/llvm-project/pull/90413