Previously, device info was returned as a queue with each element having
a "Level" field indicating its nesting level. This replaces this queue
with a more traditional tree-like structure.

This should not result in a change to the output of
`llvm-offload-device-info`.

[Offload] Use new error code handling mechanism

This removes the old ErrorCode-less error method and requires
every user to provide a concrete error code. All calls have been
updated.

In addition, for consistency with error messages elsewhere in LLVM, all
messages have been made to start lower case.

The ffi_cif structure defined in the wrapper header is smaller than the
actual structure in libffi which results in other structures being
overwritten when libffi is called, and finally in a segfault.

The patch updates the structure to the correct layout as specified in
ffi.h

https://github.com/codespell-project/codespell

% `codespell
--ignore-words-list=archtype,hsa,identty,inout,iself,nd,te,ths,vertexes
--write-changes`

This adds support for the loongarch64 architecture to the offload host
plugin.

Similar to #115773

To fix some test issues, I've had to add the LoongArch64 target to:

- CompilerInvocation::ParseLangArgs
- linkDevice in ClangLinuxWrapper.cpp
- OMPContext::OMPContext (to set the device_kind_cpu trait)

Reviewed By: jhuber6

Pull Request: https://github.com/llvm/llvm-project/pull/120173

This adds support for the riscv64 architecture to the offload host
plugin. The check to define FFI_DEFAULT_ABI is intentionally not guarded
by __riscv_xlen as the value is the same for riscv32 and riscv64
(support for OpenMP on riscv32 is still under review).

It appears that the RUNTIMES build prefers the x86-64-unknown-linux-gnu
triple notation for the host. This fixes runtime / test breakages when
compiler-rt is used as the CLANG_DEFAULT_RTLIB.