[llvm] [OFFLOAD] Add support for host offloading device (PR #177307)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

This broke our bot: https://lab.llvm.org/buildbot/#/builders/10/builds/22566
It was red before because of a failing test. This one broke the build.
>From the log
```
-- Building x86_64 plugin linked with libffi
CMake Error at /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.src/offload/plugins-nextgen/CMakeLists.txt:54 (add_subdirectory):
  The binary directory
    /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/runtimes/runtimes-bins/offload/plugins-nextgen/host
  is already used to build a source directory.  It cannot be used to build
  source directory
    /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.src/offload/plugins-nextgen/host
  Specify a unique binary directory name.
-- Building the llvm-offload-device-info tool
```

Is this an issue with the bot config or this PR?

https://github.com/llvm/llvm-project/pull/177307