[llvm] [NFC][Utils] Clone basic blocks after we're done with metadata in CloneFunctionInto (PR #118621)

[Artem Pianykh via llvm-commits]

artempyanykh wrote:

@TylerNowicki that's right – the bottom half of the stack is mainly massaging the code into a shape that makes it easier to make functional changes.

https://github.com/llvm/llvm-project/pull/118621