[CIR][CodeGen] Attach hot function attribute to CIR function

[tommymcm]

Minimized test case:

__attribute((hot)) A() {}

Failed assertion:

clangir/clang/lib/CIR/CodeGen/CIRGenModule.cpp

Line 2987 in aeac352

llvm_unreachable("NYI");

[rafasumi]

Hey @tommymcm, can I pick this up?

[tommymcm]

Hey @tommymcm, can I pick this up?

Feel free to pick up any of these issues. One note that I forgot here on testing, you need to run with optimizations enabled. For example clang -O2 -fclangir