Windows/CMake: Setting `LLVM_USE_CRT_DEBUG` to `MTd` is being ignored.

[rainerzufalldererste]

When configuring the CRT for a Visual Studio Solution on Windows via CMake GUI, setting the CRT to MT for Release, MinSizeRel, RelWithDebInfo and MTd for Debug results in Debug also having it's CRT being set to MT instead of MTd.

Steps to reproduce:

1. On Windows, open LLVM Folder in CMake GUI
2. Configure with Visual Studio 2022
3. Set LLVM_USE_CRT_DEBUG to MTd (every other CRT to MT)
4. Generate Project
5. Observe that the Debug Target also using /MT instead of /MTd

[Boris-Rasin]

LLVM_USE_CRT_* has been deprecated in favor of CMake's CMAKE_MSVC_RUNTIME_LIBRARY

c6bd873
#66850