Upgrade LLVM

[duckdoom5]

@tritao Could you please run the windows llvm workflow and upload the DebugOpt & Release versions so I can locally test and adapt the code for the new llvm version?

(I've used the 19.1.7 release tag)

[tritao]

https://github.com/mono/CppSharp/actions/runs/13562851707

[tritao]

CMake Error at cmake/modules/AddLLVM.cmake:2041 (add_dependencies):
  The dependency target "llvm-objcopy" of target "check-mlgo-utils" does not
  exist.
Call Stack (most recent call first):
  cmake/modules/AddLLVM.cmake:2107 (add_lit_target)
  utils/mlgo-utils/CMakeLists.txt:6 (add_lit_testsuite)

Might be easier to fix this one locally before sending new CI build.

[duckdoom5]

Alright, will have to do this at a later time then :/