[clang] [llvm] [OpenMP][clang] Register Vtables on device for indirect calls (PR #159856)

[via cfe-commits]

Jason-VanBeusekom wrote:

@ronlieb on a gfx908 and gfx90a I was not able to reproduce this, your example compiled and ran without issue:

```
clang++  -O2    -fopenmp --offload-arch=gfx908   -D__OFFLOAD_ARCH_gfx908__ test.cpp -o virtual_functions
test.cpp:43:9: warning: type 'C' is not trivially copyable and not guaranteed to be mapped correctly [-Wopenmp-mapping]
   43 |     h = host_C.foo(3);
      |         ^~~~~~
1 warning generated.
test.cpp:43:9: warning: type 'C' is not trivially copyable and not guaranteed to be mapped correctly [-Wopenmp-mapping]
   43 |     h = host_C.foo(3);
      |         ^~~~~~
1 warning generated.
./virtual_functions 
```

https://github.com/llvm/llvm-project/pull/159856